WBBSE Chapter 1 Exogenetic Processes And Resultant Land Forms Long Question And Answers

Question 1. Describe the various works of landforms formed due to erosional works of rivers.
Or
Describe with sketches three major landforms developed by the erosional work of rivers.
Answer:

Erosion and Its Effects on Landforms

The river performs three activities: erosion, transportation and deposition.

The landforms formed due to the erosional works of a river are:

1. Canyons:

• The canyons are formed in the mountainous regions of arid climatic regions. The rivers which flow through these valleys are generally snowed. They have high erosive powers due to great velocity.
• Downcutting of the valleys is prolonged while side cutting is negligible, as there is no rainfall in this region and no tributaries meet the main river.

Example: The Grand Canyon of river Colorado.

2. Gorges:

• In humid mountainous regions, the rivers flow with great velocity and have great erosive power.
• The downcutting of the rivers makes the valleys very deep. At the same time, side-cutting of the valleys occurs due to weathering, mass wasting and other activities.
• Thus, the valleys become wider and look like the letter ‘V’. Example-Valley of river Kali in Nepal.

 

3. Waterfalls:

• In the course of the river, if hard and soft rock beds lie alternately, the soft rocks get eroded very fast and the hard rocks stand out.
• This leads the water of the river to fall from a considerable height over a steep slope.
• Thus, a waterfall is formed. Example—The Angel waterfalls in the course of river Churun in Venezuela is the highest waterfalls in the world.

4. Potholes:

• As the river flows, the rocks and boulders carried along with the water rub against the floor of the river bed and cause the formation of small depressions due to abrasion.
• These are known as potholes. Example—Numerous potholes are present on the bed of river Tista.

 

5. Plunge pools:

• As the water falls from a height with great velocity, the rock beds at the base of the waterfalls get eroded, and huge depressions are formed there.
• These are formed due to abrasion and the plunging of the water and hence they are called plunge pools. Plunge pools are potholes of bigger dimensions.

6. Interlocking spurs:

• In mountainous regions, the hard rocks or mountain ridges may lie in such a way that the river has to take frequent turns to avoid these obstructions while flowing.
• The river erodes the foothills of these mountains to carve out its own path of flow. A distant view of the landscape looks as if the mountains are interwoven or interlocked.
• Such mountains are known as interlocking spurs.

 

7. Truncated spur:

• A truncated spur is a blunt-ended, sloping ridge which descends towards a valley.
• Its abrupt termination is normally due to erosion by glaciers and rivers.

Example: Truncated spurs are seen in the valleys of the rivers Tista, Torsa, Mahananda, etc.

Question 3. Describe the various landforms formed due to the depositional works of rivers.
Answer:

The various landforms formed due to depositional works of rivers are—

1. Alluvial cone and alluvial fan:

• As the rivers emerge from the mountains, they erode heavily and flow with great speed.
• However, when they leave their mountainous course and enter the plains, they suddenly lose their speed.
• Thus, the carrying capacity of the river is reduced considerably.

Exogenetic Processes Overview

• Hence, it deposits huge amounts of rocks, pebbles, sand, silt, clay, etc. at the foothills of the mountains.
• These depositions look like a cone and are called alluvial cones.
• If the cones spread wider, they are called alluvial fans.

Example—Such alluvial cones and fans are present at the foothills of the Himalayas in the course of different tributaries of river Ganga.

2. Sand bars and islands:

• In the middle course, the river is unable to flow with great velocity. Hence, it cannot carry the huge amount of load brought down from the mountains and starts depositing them on the river bed.
• These depositions accumulate day after day and form sand bars or river islands.
• The rivers thus bifurcate at regions when it encounters such a sand bar along the flow.
• Such bifurcated channels are known as braided channels.

Example: The Majuli island in the Brahmaputra river is the largest river island in India.

3. Flood plains:

• In the middle course, the valleys of the river are wide but less deep.
• During the rainy season, when the water volume in the channel increases, the river floods the adjacent areas.
• The silt, clay and mud present in the river water also flow out and spread over the area.
• When the flood recedes, a part of the flood water flows back into the river and some percolates down to recharge the underground water table.
• However, the silt and clay remain spread over the region. These silt deposits accumulated over the years form flood plains.

 

4. Natural levees:

• On the plains, the silt, clay and sand particles flowing out of the river channel during floods get accumulated and compact on the banks of the river.
• These naturally forming accumulations rise in height forming a narrow belt of ridges and these are known as natural levees.
• Natural levees act as natural embankments and help in checking floods

Delta:

• In the lower course of the river, the slope of the land becomes so negligible that the river cannot carry its load any further.
• It deposits the load gradually near the mouth.
• These continued depositions eventually form small islands, encountering which the river channel bifurcates into several distributaries before meeting the sea.
• The islands formed to resemble a triangle or the Greek alphabet ‘A’. Hence, the region is called a delta.

Question 4. Discuss the favourable conditions for delta formation.
Answer:

The conditions favourable for the formation of a delta are—

• The rate of deposition of silt and other materials by the river and its distributaries must be more than the rate of removal of the deposition by the sea waves.
• The rivers should have a long course and should have a number of tributaries so that the eroded materials brought down altogether are sufficient for the development of a delta.
• The river should not be turbulent and speedy near the mouth so that silt can easily deposit there.
• The continental shelf where the river meets the sea should be wide and gentle in slope so that the sediments brought down can easily deposit there. A steep slope of the continental shelf will wash down the sediments into the deep sea and hinder delta formation.
• Deltas are easily formed if the prevailing wind direction in the region is opposite to that the direction of the river.
• Deltas are formed easily in regions where the sea is a little enclosed with the land rather than in regions with open seas.
• Almost stable conditions (not subject to any rejuvenation or submergence) of the sea coast and oceanic bottom will allow the deposits to settle down.
• Finer sediments will get carried away in suspension deeper into the sea. Very coarse and large size sediments would settle at the river bed. So, medium-sized sediments are the most suited for delta formation.

Question 5. Compare the works of a river in its three courses.
Answer:

A river performs different actions in its different courses. The actions of the river in its three different courses are—

Question 6. How has the change in climate influenced the islands of Lohachara, New Moore and Ghoramara?
Answer:

The change in climate influenced the islands of Lohachara, New Moore and Ghoramara

Climatic changes have endangered the existence of the islands of the Sundarbans to a great extent. Global warming has caused the melting of ice caps and glaciers to such an extent that, the sea level has risen considerably. This has led to the submergence of numerous small islands. The large islands of Lohachara, New Moore and Ghoramara have also faced submergence and have been named Vanishing islands’. Numerous villages and agricultural fields have submerged, and thousands of people have become ‘climatic refugees’.

1. Lohachara Island:
   • The Lohachara island existed in the Sundarban region near the mouth of the river Hooghly.
   • In 2006, the island was submerged completely. In 2009, it started re-appeared, but presently it lies submerged.
2.  New Moore island:
   • New Moore island lies 2 km from the mouth of the river Hariyabhanga. It is a part of the Ganga- Brahmaputra delta region.
   • In 1970, the island was submerged as an aftermath of the super cyclone ‘Bhola’. In 1974, the size of the island was 2500 sq.m according to satellite images.
   • However, at present, it lies completely underwater as a submerged bar or bank.
3. Ghoramara island:
   • The Ghoramara island lies 92 km south of Kolkata, north of the Sagar Islands at the mouth of river Hooghly and east of the mouth of river Haldi in the Bay of Bengal.
   • This is an island in the Sundarban region. In 1951, the size of the island was 38.23sq. km, but by 2011, the size reduced to a mere 4.37sq.km.
   • Experts predict that the island will totally disappear due to submergence in the near future.

Question 7. Mention the extent of the different courses of river Ganga.
Answer:

The extent of the three courses of river Ganga is

Question 8. Discuss the various types of erosion.
Answer:

Erosion by rivers can be divided into two types—

chemical erosion and mechanical erosion, which further involves various methods.

Chemical Erosion:

• Solution:
  • This process involves the dissolution of soluble materials.
  • The soluble materials are removed from their parent rocks by the processes of disintegration and decomposition.

2. Mechanical Erosion:

• The force of water: themayErosionrunningThefallIn the off removed water. river the wall valleys, materials of the valleys due to continuous hitting of water, and may get carried away to distant places with the flowing water.
• Attrition: The rock fragments are already broken away from the valley walls or river bed strike against each other and break into smaller fragments in this process. These fragments are carried with the water in suspension and transported down the channel.
• Abrasion: This process involves the removal of loosened rock materials from the valley walls and floors with the help of the tools of erosion. The rock fragments carried by the river collide and scratch against the river valley and erode materials from there, thus deepening and widening the valley.
• Hydraulic action: The bubbles created in the river water in the course of flow may burst together and produce sound waves, which can gradually break down the rock fragments into smaller parts.

Question 9. On which factors does the carrying capacity of a river depend?
Answer:

The carrying capacity of a river depends upon the following factors-

Question 10. By which methods does the river carry its load?
Answer:

The river carries its load by the following four methods—

Question 11. Under which conditions does the river deposit its load?
Answer:

A river deposits its load under the following situations—

1. Volume of water:

Depositions occur when the volume of water in the river reduces.

The volume of water reduces in the following situations:

• When the river enters a region of low rainfall.
• During periods of droughts.
• In dry seasons
• In limestone or sandstone regions where water percolates down.

2. Reduced slope:

The velocity of the river reduces if it flows over land with a gentle slope and thus the reduced velocity enhances the deposition process.

3. Bed load:

If the amount of sediment carried by the river increases, as in the case of the middle and lower course of the river, the flow of the river becomes sluggish and thus it deposits much of its bed load to reduce the amount of sediment being carried.

Question 12. Mention the effects of the global climatic change on the active part of the Ganga-Padma-Meghna delta.
Answer:

The effects of the global climatic change on the active part of the Ganga-Padma-Meghna delta are—

• Rise in temperature: During the period from 1980 to 2017, the temperature of water of the rivers of the Sundarbans region has risen by 0.5°C per decade. This rise in temperature has caused great harm to the mangrove ecosystem.
• Cyclones and monsoon wind: The global climatic change has increased the frequency of the cyclones occurring in and hitting the Sundarbans. Clearing the mangrove forests to make way for human settlement has magnified the impact of the cyclones in this region.
• Rise in sea level: The global rise in temperature is causing the ice caps to melt at the poles. This, in turn, is leading to the rise in sea level, posing a great threat to many islands and island nations of the world. Several islands of the Sunderbans are facing a similar danger. Example— Lohachara, South Talpatti.
•  Increase in salinity: The rise in sea level is causing the water and soil of the Sundarbans to become saline. This is affecting agriculture, the drinking water of the region, etc.

Question 13. How are waterfalls formed in the course of a river?
Answer:

Waterfalls formed in the course of a river:

When the water of a river plunges from a higher elevation to a lower elevation, it is known as a waterfall. In the course of a river, if hard and soft rock beds lie alternately horizontally one above the other, or diagonally, the harder rocks are less eroded and softer rocks are highly eroded by the river. This gradually gives rise to a steep slope over which the river plunges downwards. A waterfall may also be formed at a knick point along the course of the river where there is a sudden change of elevation in the longitudinal course.

Example: The famous Niagara falls lies along the course of the Niagara river in the USA.

Question 14.  Classify waterfalls.
Answer:

Waterfalls

Waterfalls can be classified into three types according to the slope of the land and the volume of water in the waterfalls—

Question 15.  Explain why the river’s main work in the lower course is deposition.
Answer:

The river’s main work in the lower course is deposition:

• In the lower course of the river, the slope of the land over which the river flows is negligible.
• As a result, the flow becomes sluggish. Also, the amount of bed load carried in this course is huge.
• The river loses all its erosional and transportation capacities.
• Thus, the huge amounts of load brought down from the upper and middle courses, get deposited along the lower course of the river.
• Depositional features seen here are flood plains, natural levees, deltas, etc.

Question 16.  Why do in their the mountainous rivers mainly course?
Answer:

The rivers mainly cause erosion in their mountainous course because—

• The mountainous regions have rugged terrain and steep slope, which increases the velocity of the flowing water.
• The valley walls and floors get highly eroded by the methods of hydraulic action, abrasion and attrition.
• The amount of sediment transported by the river in this course is much less and thus the erosive power of the rivers is more.

Question 17.  How is a delta formed in the lower course of a river? Or, Explain why a delta is formed at the mouth of a river.
Answer:

The deltas can be classified into four types according to their shapes—

• Loses its velocity and carrying capacity. The huge amount of sand, silt, clay, etc., brought down from the mountains is deposited in this region.
• The saline water at the mouth of the river where it meets the sea helps these deposited materials to get compacted.
• Thus, new islands are formed in the lower course of the river over a vast region from these deposited sediments.
• These islands are known as deltas.
• It must be noted that the rate of deposition of sediments must exceed its removal rate by the sea waves as one of the factors affecting delta formation.

Example:  Te largest delta in the world has formed at the mouth of the rivers Ganga-Brahmaputra.

 

Question 18.  Classify deltas.
Answer:

The deltas can be classified into four types according to their shapes—

The deltas that look like an arc of a circle or a bow at the region or side that meets the sea, are known as arcuate deltas.

Example: The deltas formed by the river Ganga, Nile, Po, Rhine, Hwang Ho, etc. are arcuate deltas.

• The deltas that resemble the foot of a bird pointing towards the sea i.e., finer materials
• The deltas that are vaguely V-shaped with curved sides are known as cuspate deltas. E.g.-The delta formed by the river Ebro.
• The deltas formed due to the filling of the estuaries of the rivers are known as estuarine deltas. E.g.-The delta formed by the river Rhine.

Question 19.  How are oxbow lakes formed?
Answer:

Oxbow lakes are Formed as follows:

Oxbow lakes are formed mostly at the end of the middle course and the beginning of the lower course of a river.

• The curvatures of the meander loops of the river are enhanced due to continued lateral erosion by the rivers in their middle course.
• Thus, the two ends of the individual meander loops gradually come closer and their mouth is clogged by the sediments deposited by the river.
• The meander loop is eventually abandoned as the river straightens its course. Thus, the water in the abandoned loop forms an oxbow lake.
• Numerous oxbow lakes are seen along the course of river Ganga and its tributaries.

 

Question 20.  Why are ‘V-shaped valleys formed in the upper course of a river?
Answer:

‘V-shaped valleys formed in the upper course of a river

The section of the river flowing through the mountainous region is known as the upper course of a river. The shape of the river valley formed in this region due to downcutting is like a V.

The causes of the formation of the ‘V-shaped valleys are:

• Slope of land:
  • The slope of the land is steep in mountainous regions. This causes the river to flow with great velocity.
  • The high velocity of the river and the rock fragments carried with it collide with the river bed and cause more downcutting than side cutting of the valleys.
  • This makes the river valley narrow but deep.
•  Heavy rainfall and weathering:
  • In mountainous regions that receive heavy rainfall, the rate of weathering by mechanical and chemical processes is high.
  • The dissolving of certain minerals (like limestone) and mass wasting removes huge amounts of rock debris from the region.
  • This makes the river valleys deep ‘And V-shaped and gradually the valleys start becoming wide due to lateral erosion also.

Others:

• Sometimes, landslides in river valleys are very steep, causing them to widen and become ‘V-shaped.
• The meeting of tributaries with the main river also makes the valleys ‘V-shaped.

Question 21. How are flood plains formed?
Answer:

• Flood plains are formed in the middle course of the river due to the deposition of silt. In the middle course of the river, when the volume of water suddenly increases due to heavy rainfall or due to snow-melt water draining into the river in the upper course, the excess water flows out of the river channel towards the adjacent plains on both sides of the river banks.
• Huge amounts of sand, silt and clay flow out with this water and spread all over the area during times of flood.
• When the flood water recedes, some of the water flows back into the river, while some percolates underground.
• The silt and clay spread over the area form a thin layer of soil over the area. When this process continues year after year, the region develops into a new landform called a floodplain. Large flood plains are seen on both the banks of river Ganga and river Brahmaputra.

Question 22.  How do waterfalls move backwards?
Answer:

Waterfalls move backwards:

The plunging of water of a river from a height downwards, forms a waterfall.

• Such difference in height within the river course occurs due to the presence of hard rock beds alternated with soft rock beds.
• As the water plunges from a height, it creates a plunge pool at the foot of the waterfall. This plunge pool increases in dimension over time and the rocks of the wall seem to hang over a hollow. After a period of time this hanging wall collapses, thus the waterfall seems to move backwards, towards its source.
• Example—The backward movement of the Chitrakoot waterfalls on river Indravati can be clearly understood.

Question 23. How are the Sundarbans being affected by climatic changes?
Answer:

The climatic changes all over the world are also affecting the Sundarbans in the following ways—

• Due to the increased rate of global warming, the temperature of the earth will increase by 2-4“C by 2050. The amount of ice that will be melted due to this rise in temperature will increase the level of seawater. If the sea level rises by lm, most of the islands in the Sundarbans would submerge. A few already have.
• The rise in sea level, is also turning the rivers of this region saline. This, in turn, is affecting the plants and animals of the region.
• Saline soil is affecting the agriculture of the region and causing a shortage of food.
• Increase in temperature is causing frequent cyclonic storms in this region.

Question 24.  What is the role of a river as a part of the water cycle?
Answer:

The role of a river as a part of the water cycle

• The rivers help in the circulation of rainwater from one place to another. The rivers help to prevent the rainwater from remaining arrested in a particular region.
• The water present on the earth’s surface and in the atmosphere circulates through the hydrological cycle. The sun evaporates huge amounts of water from rivers, lakes, oceans and other water bodies. The water vapour thus created, concentrates and forms clouds.
• These clouds cause snowfall and rainfall. The water coming from the rain or melting of snow accumulates and flows down the slope of the mountains as rivers. The water in the rivers once again evaporates and forms vapour.
• A part of it also percolates down and recharges the underground water table. The rest of the water flows into the ocean. This is how the river plays an important role in the water or the hydrological cycle.

Question 25.  Why are oxbow lakes formed in deltaic regions?
Answer:

The oxbow lakes are formed in deltaic regions due to the following reasons—

• Meandering rivers: The slope of the land becomes negligible in the deltaic region. Thus, the river cannot flow with great velocity and takes a turn wherever it is obstructed.
• Erosion at the curves of meanders: As the river starts meandering, erosion occurs at the concave side and deposition occurs at the convex side.
•  Increase in the curve of the meanders: As the processes of erosion and deposition occur simultaneously in a meander, the curvature increases, and the two ends of the curve come very close to each other.

As the ends of a curve of a meander come very close to each other, the curved part is cut off due to deposition from the main flow and the river continues to flow in a straight path. The enclosed body of stagnant water thus left behind becomes an oxbow lake.

Question 26. What are constructive deltas and destructive deltas?
Answer:

Constructive deltas:

The rivers bring down huge amounts of sand, silt and clay from the upper course and deposit them over vast areas to form a delta at its mouth. The size of the delta goes on increasing as more and more deposits are brought in. This is called a constructive delta.

Constructive deltas can be of two types:

1. Tongue-shaped
   • Example: Delta of river Nile
2.  Bird foot shaped
   • Example: Delta of river Mississippi

Destructive deltas: The deltas which go on changing their shapes and sizes due to the action of waves and tides, are called destructive deltas.

Example:

Delta formed by river Rhone is highly a wave-dominated delta.

Question 27.  Why do floods occur frequently in the lower course of the river?
Answer:

The lower course of the river is frequently flooded due to the following reasons—

•  The river contains a huge volume of water in this course. However, the slope of the land is so negligible that the water cannot flow with great velocity towards the sea.
• The maximum of the load brought down by the river is deposited in this region. Thus, the depth of the river channel gradually decreases.
• During the rainy season, as the volume of water in the channel in the upper course increases the lower course cannot hold the huge volume of water, hence the banks on either side get flooded.

Question 28. Why have numerous islands and sand bars formed on the river Brahmaputra?
Answer:

Numerous islands and sandbars have formed on the river Brahmaputra because—

• The course of river Brahmaputra flowing through Assam is the middle course. Hence, the river flows with less velocity.
• The load brought down by the river gets deposited on the river bed and creates sand bars.
• Numerous tributaries join the river Brahmaputra and contribute a huge amount of water as well as eroded materials.
• Thus, more sand bars are formed and each of them grows larger in size. Example—Majuli island has been formed in a similar way.

Question 29.  What are the different exogenetic processes?
Answer:

The exogenetic processes can be broadly divided into three parts—

• Degradation: Through this process, the existing landforms are lowered in height.
  • Example: Residual hills.
• Aggradation: By this process, the height of the existing landforms is increased by the deposition of materials brought down by rivers, glaciers and winds due to erosion.
  • Example: Flood plains, loess plains, deltas, etc.
• Biotic activities: Sometimes, changes in landforms occur due to biotic activities.
  • Example: . Ponds, wetlands or depressions may get filled up with mosses, plants bushes, fruits, flowers, etc. People may cut down mountains to construct roads, railway lines, etc.
  • Shallow seas or gulfs may be dammed to reclaim land from the water.

Question 30.  How is landform levelled by the process of graduation?
Answer:

• Gradation is the process of levelling rugged and uneven land into a smooth and even landform.
• It is the combined outcome of the process of degradation and aggradation. A graded profile is one in which no further erosion or deposition takes place.
• Gradation is the combination of both degradation and aggradation.
• The high hills and rugged topography are lowered and levelled due to erosion by wind, water, snow, etc. This is known as degradation.
• Through the process of aggradation, the low-lying regions, the depressions and gaps are filled up by the deposition of eroded materials brought down by rivers, glaciers or wind. Degradation and aggradation processes go on continue unless the graded profile is attained.

Question 31.  Differentiate between gorges and canyons
Answer:

Gorges and canyons both are deep valleys created due to river erosion. However, there are some minor differences between the two.

The differences between them are:

Question 32.  Differentiate between alluvial cones and deltas.
Answer:

The differences between alluvial cones and deltas are as follows:

Question 33.  What is a canyon?
Answer:

Canyons:

Canyons are formed when the river flows through a dry, rainless region where the rate of lateral erosion is far less than the rate of vertical erosion. Prolonged downcutting by the rivers through the soft rocks forms long and narrow steep-sided valleys. These valleys formed resemble the shape of the letter T and are known as canyons.

Example: Grand Canyon.

• The limit of maximum downward erosion by a river is known as the base level of erosion. The base level of erosion can be further divided into grand base level, temporary base level and local base level.
• The sea level becomes the grand base level beyond which no dryland can further erode.
• There may also be a temporary base level of a river course depending on the presence of lakes or beds of hard and soft rocks along the course.
• The local base level of erosion on the other hand depends on the confluence of the tributary stream with the mainstream.

Question 34.  Describe a few landforms formed due to erosional works of glaciers.
Answer:

The glaciers erode the valley or region through which it flows and form several landforms. A few of them are as follows—

1. Cirque:

• The glacier erodes by the processes of plucking and abrasion At the source of the glacier, the mountain wall is eroded heavily and the landform thus formed looks like a huge armchair.
• This is known as a cirque Rock basin formed at the floor of the cirques gets filled up with water after deglaciation and is known as cirque lakes or tarn lakes.

Cirques are known by different names at different places Cirques can be divided into three parts—

• Steep wall at the back,
• Semi-circular depression in the middle
• Threshold or hunch at the lower part. The cirques may get filled with snow-melt water and form lakes For Example—Such landforms are seen in the glacial regions of the Himalayas, Alps, etc.

2. Arete:

• In the snow-covered mountainous region, two or more glaciers can originate from different slopes of a single mountain
• Thus a number of cirques will be formed in the same mountain Due to headward erosion, the cirques may get deeper, and the portion between two adjacent cirques lie like a steep, sharp narrow wall.
• This is called an arete. If the mountain has three or more aretes it forms a pyramidal peak. The tip or peak of such a pyramidal peak is called a horn.

Example:  The Matterhorn peak.

3. Hanging valleys:

In a glaciated region, the main or trunk glacier carries a greater volume of ice than the tributary glaciers.

• Thus the main glacier has greater erosive power than the smaller tributary glaciers.
• Hence, the main glacier forms deeper valleys and the tributary glaciers form comparatively less deep valleys.
• These are not visible as long as the ice cover remains. When the glaciers melt or recede, the small valleys are found to be hanging over the huge deep valleys, due to different rates of erosion during their formation.
• Such valleys are called hanging valleys.

4. U-shaped valley:

• In a mountain glacier, the glacier descends from the cirque and flows through the valley.
• The intensity of side erosion or lateral erosion is almost the same as the intensity of vertical erosion of the glacial valley by the processes of abrasion and plucking.
• Thus, the valley developed looks like the letter ‘U’. These valleys are called U-shaped valleys.

5. Fjord:

In regions where the mountain glaciers meet the coast directly, the valleys may be eroded so deep that the base or bed of the valley may lie lower than the sea level.

• When the ice melts or recedes these depressions get filled up with seawater.
• Such regions look like valleys that have been submerged in ocean water, while the ridges stand out.
• These submerged valleys are known as fjords.
• Such a coast is known as a fjord coast. Examples of fjords are seen in Norway and Finland.

 

 

6. Roches mountaineer:

• In the path of a glacier, if a hard rock stands like an obstruction, the glacier rides over it while crossing it.
• In this process, the side over which it rides gets smoothened and polished by the rocks and pebbles.

 

7. Crag and tail:

• Along the path of the glacier if there lies a volcanic rock it projects above the ground as a resistant rock.
• These volcanic rocks offer resistance to the flow of ice and thus the side facing the direction of flow becomes steep due to erosion.
• This is known as a crag. The other side being sheltered by the ice becomes elongated and has a gentle slope.
• This elongated side is known as the tail. Crag Hard rock outcrop

 

8. Glacial stairways:

• When the glaciers descend from very high mountains into valleys, they develop steps or stairs along the walls of the valleys through the processes of abrasion and plucking.
• The steps may develop due to unequal distribution of load in the glacier or alternate alignment of hard and soft rock beds.
• These steps are known as glacial stairways. Further, small depressions formed in these steps get filled up with snowmelt water, later
• . These depressions are known as paternoster lakes.

 

Question 35.  Describe a few landforms formed by the depositional works of glaciers.
Answer:

The depositional works of glaciers can be broadly classified into two parts—

1. Depositional landforms altitudes:

• Moraines:
  • The debris of rocks and pebbles that the glaciers carry as they flow through the valleys, get deposited in parts along the sides, bed or at the end of the glaciers
  • . These are known as moraines.
  • They are named side moraines or lateral moraines, medial moraines and end or terminal moraines based on their locational aspect.
• Karnes: At the end of the glacier, as the ice melts, the rocks, pebbles, sand and gravel brought down by the glacier get accumulated and are deposited in triangular shapes, resembling deltas of rivers. They are called kames. Narrow flat-topped terraces like ridges are called kame terraces.

2. Depositional landforms in lower altitudes:

• Glacial erratics:
  • The glaciers bring down rocks and boulders along with them in their course.
  • When they melt, these rocks and boulders may get carried to distant places with the snow-melt water, and get deposited there.
  • These rocks have no similarities with the local rocks of that region. Such rocks are called glacial erratics.
• Eskers:
  • The rocks, sand, clay, pebbles, etc. brought down by glaciers may get deposited like low ridges at the foothills of the mountains.
  • They may be curved and branched. These ridges are called eskers.
• Example: Punkaharju esker in Finland.

3.  Drumlins:

• • When boulder clay is deposited in large heaps that look like inverted boats, they are known as drumlins.
  • A number of Compare the works of rivers and glaciers drumlins lying in a region look like a ‘basket of eggs topography’.

4. Boulder clay:

The accumulation of sand, clay, rocks and boulders at the base of the valley after the glacier melts is known as boulder clay.

5. Outwash plains:

• At the end moraine, where the glacier melts and gives rise to the river, the rocks, pebbles, clay and sand brought down by the glacier are carried as bed load by the river water and spread over extensive areas.
• The plains thus formed are called outwash plains.
• The big chunks of hard ice that come along with the rock debris, make depressions, in the ground these are called kettles.
• When the hard ice melts, these depressions get filled up with water and form kettle lakes.

6. Knobs:

Rocks and pebbles brought down by glaciers and carried along with flowing water are deposited on the outwash plains like domes or low hillocks, they are called knobs.

 

Question 36.  Compare the works of rivers and glaciers.
Answer:

The comparison between the works of rivers and glaciers is as follows—

Question 37.  How are pyramidal peaks and hanging valleys formed?
Answer:

Pyramidal peaks and hanging valleys formed:

• Hanging valleys: In a glaciated region, the main or trunk glacier carries a greater volume of ice than the tributary glaciers.
• Thus the main glacier has greater erosive power than the smaller tributary glaciers.
• Hence, the main glacier forms deeper valleys and the tributary glaciers form comparatively less deep valleys.
• These are not visible as long as the ice cover remains. When the glaciers melt or recede, the small valleys are found to be hanging over the huge deep valleys, due to different rates of erosion during their formation. Such valleys are called hanging valleys.

Question 38.  Differentiate between river valleys and glacial valleys.
Answer:

The differences between river valleys and glacial valleys are as follows-

Question 39. Why are waterfalls formed from where the corrie is formed, the ice seems to tear hanging valleys.
Answer:

• In hilly regions through which glaciers flow, the main glacier being longer, wider and more extensive erodes much more than the small tributary glaciers.
• Thus, the valley of the main glacier is deeper than the valleys of the small tributary glaciers.
• When the ice melts, the small glacial valleys seem to hang over the main valley due to differences in height.
• The rivers formed due to the melting of the glaciers flow through these glacial valleys.
• The water pouring in from the tributary glacial valleys into the main valley jumps downwards due to differences in elevation, thus creating waterfalls.

Example:  Vasudhara waterfalls near Badrinath. The rivers flowing through this region gradually erode the glacial valleys and try to reduce the slope of the land.

Question 40.  What are varves?
Answer:

Varves:

• Varves are circular deposits of sediments found in glacial lakes. Each valve has two layers of deposits.
• The light-coloured sandy deposits and the dark-coloured silt deposits. In the summer reason, when the snow melts and the speed of the glacial melt water is greater, the heavy sediments are deposited, while the lighter ones are carried in suspension. As the winter sets in, the rate of melting is lowered and also there is less meltwater flowing.
• As a result, the sediments in suspension are also deposited. Every year a new set of sediments are deposited in different circles. Enumerating the number of circles helps to calculate the age of the lake.

Question 41.  How is an ideal glacier formed?
Answer:

An ideal glacier is formed by the following processes—

• Sublimation: The ice crystals directly change into vapour by this process.
• Crystallisation: The small crystals of snow are broken and compacted into large crystals to form ice. This ice serves as the source of a glacier.
• Melting: Sometimes the ice melts partially into the water, and sometimes the water crystallises into ice. These processes lead to the formation of glaciers. 
• Regelation: This is the phenomenon of melting ice under high pressure and freezing again when the pressure is reduced. This influences the structure of the ice crystals and leads to the formation of glaciers.
• Compaction: As more and more snowfall occurs the lower layers of snown get compacted into ice this helps in the information of glaciers.

Question 42.  What are moraines? Classify the moraines.
Answer:

Moraines:

The glaciers erode materials from the walls and beds of the valleys as they flow downwards. These rock debris are deposited along the sides, end or ground of the glacial valley as glacial till or deposits in the form of ridges. These are known as moraines.

Classification:

The moraines can be generally divided into four types based on their locational aspect.

• Moraines deposited along the sides of the glacier are called side moraines or lateral moraines.
• Two lateral moraines meet to form the medial moraine. They are found on the top and on the inner side of an existing glacier.
• The end moraine or terminal moraine is formed due to depositions at the end of the glacier, where it starts to melt.
• The moraine deposited on the base or on the floor of the valley is called a ground moraine.

Question 43.  Differentiate between mountaineers and drumlins. Differentiate between kame and delta.
Answer:

The differences between kame and delta are as follows—

Question 44. Differentiate between Kame and delta.
Answer:

The difference between Kame and delta are as follows-

Question 45.  Differentiate between continental glaciers and valley glaciers
Answer:

The difference between glacier and valley glaciers

Question 46.  Differentiate between bergschrund and crevasses
Answer:

The difference between bergschrund and crevasses are as follows-

Question 47.  What is a knick point?
Answer:

Knick point:

After the rejuvenation of a river, the point lying between the old slope and the new slope is known as the knick point. Waterfalls are formed at the knick points as the difference in the level of the old slope and the new slope creates a considerable difference in height for the water to jump. The knick point gets eroded gradually with time and matches the graded profile of the region.

 

Question 48. What are mountain or valley glaciers?
Answer:

Mountain or valley glaciers:

The glaciers that flow through the valleys in high mountainous regions are called valleys or mountain glaciers. E.g- Gangotri

Question 49. What are Piedmont glaciers?
Answer:

Piedmont glaciers:

The glaciers formed due to the coalescence of several mountains or valley glaciers at the foothills of the mountains, are called piedmont glaciers.

Question 50. What are avalanches?
Answer:

Avalanches:

In snow-covered mountainous and glacial regions, sometimes huge volumes of ice may slide down mountain slopes due to their large weight and gravitational pull. These are called avalanches. They can be so powerful at times, that they may cause earthquakes and devastate forests or habitations coming their way.

Question 51. What is an iceberg?
Answer:

Iceberg:

The huge blocks of ice that float on the oceans are called icebergs. In higher latitudes, generally, huge blocks of ice break away from the continental glaciers and float in the adjacent oceans. They move towards lower latitudes with the help of ocean currents. Only 1/9 th part of an iceberg floats above the water. The rest remain submerged. The famous ship Titanic was wrecked on its first voyage due to its collision with a huge iceberg.

Question 52. What are pyramidal peaks?
Answer:

Pyramidal peaks:

At the source of the mountain glaciers, deep armchair-like depressions are formed on the walls of the mountains due to erosion. These are called cirques or corries. The steep narrow wall between two adjacent cirques or corries is known as aretes. If there are three or more cirques on the different faces of the mountain, the aretes meet at a steep and sharp point or peak. This is called a pyramidal peak. Example— Matterhorn peak is a famous pyramidal peak in the Alps.

Question 53. Describe some of the landforms formed by wind erosion.
Answer:

The work of wind can be most prominently seen in the hot dry desert regions.

The landforms formed by erosional activities of wind are—

1. Ventifact

• In desert regions, when the windward side of a rock becomes smooth and polished due to abrasion caused by wind blowing from a single direction, it is called a ventifact.
• The other faces of the rock remain rough and unpolished.

2. Dreikanter:

• In desert regions, if the wind direction changes with changes in seasons, abrasion polishes all the faces of the rocks at different times of the year from different directions.
• Thus, rocks with three polished and smoothened sides are formed. Such a rock is called a dreikanter.

3. Mushroom rock:

• In desert regions, the effect of abrasion is more actively felt at the lower heights than at the upper heights.
• In a rock mass composed of soft rock beds at the bottom and harder rocks at the top, the lower rock beds are eroded faster than the upper beds due to abrasion
• Thus, the landform formed has a narrow base and a flat broad top.
• This resembles a mushroom and is known as a mushroom rock.

 

4.  Zeugen:

• In desert regions where soft and hard rock beds lie parallel to the earth’s surface, the soft rocks are eroded and soft rock Hard rock Furrows hollows are formed.
• The hard rocks lie above them like caps. Thus, a landform created with a broader base than the top resembling a capped inkpot is known as a zeugen.

 Yardang:

In desert regions, if hard and soft rock beds lie parallel to each other in alternate ctr the soft rocks get eroded very fast due to abrasion. The hard rocks are less eroded and lie as hanging ridges stretching parallel to each other separated by grooves. Such a feature is known as a yardang.

 Yardang: 

In desert regions, if hard and soft rock beds lie parallel to each other in alternate strips, the soft rocks get eroded very fast due to abrasion. The hard rocks are less eroded and lie as hanging ridges stretching parallel to each other separated by grooves. Such a feature is known as a yardang.

 

5. Furrow:

• In desert regions, high-velocity winds carry rock fragments and pebbles along with them, that work as tools of erosion.
• When these rock fragments hit against the large standing rocks, they form long narrow grooves on the rocks due to erosion. These narrow long grooves formed on the standing rocks are known as furrows.

6. Millet seeds sand:

• In desert regions, as the wind blows over the rocky surface, the rock fragments hit against each other and break down into smaller fragments that resemble the seeds of millets.
• These small fragments are thus called millet seeds sand. Formation of the millet seeds sand leads to the formation of sand particles due to further erosion.

8. Blowouts:

• The speedy winds in desert regions often blow out or deflate sand particles from a region.
• Thus, a number of small or big depressions are formed known as blowouts or depression hollows.
• These are known as ‘hands’ in Rajasthan. The hands may get filled with water to form saltwater lakes called playa lakes.

9. Pavements:

• These are extensive stretches of stony surfaces formed in the desert due to the deflation of the wind.
• Pavements consist of angular or rounded rocky fragments in a matrix of finer sand, silt and clay-sized materials.
• They are locally known by various names in various places. In the Sahara desert, they are known as reg or hammada.

Question 54.  Describe some of the depositional landforms formed by wind action.
Answer:

The depositional landforms formed by wind action are as follows—

1. Dunes:

In sandy deserts, if the winds carrying huge amounts of sand are obstructed by the presence of trees, plants, rocks or bushes, the wind loses speed which leads to the deposition of sand. Gradually, the sand accumulates into large heaps and forms sand dunes.

Dunes are classified into the following types—

 Barchans:

• The barchan is a transverse sand dune that is found in the desert region. It stands across the direction of the wind.
• It looks like a crescent moon. The middle part of the barchan can be 15-30m high. It has two horns on either side which move forward as the wind blows.

 

Seif dunes:

Longitudinal dunes parallel to the direction of wind form the seif dunes, Barchans gradually transform into seif dunes when the sand from the central portion gets eroded away and the two horns form two separate dunes.

Star dunes:

• In desert regions, winds blow from different directions during different times of the year.
• Thus, dunes are formed in different directions. Star dunes are formed by variable winds.
• They grow vertically and do not migrate laterally.

A star dune has multiple slip faces, a central peak and three or more arms extending radially.

•  Akle dunes: A number of barchans lying side by side like a chain from akl6 dunes. They look like a long serpentine ridge. The front part of the curve of the ankle dunes is called languid, and the rear part is known as the paranoid.
•  Transverse dunes: Elongated dunes lying at right angles to the direction of the prevailing wind are known as transverse dunes. These dunes have a steep leeward side and a gently sloping windward side. They appear as wave-like features.
• Parabolic dunes: These dunes develop in partially stabilised sandy terrains and form a U shape. Parabolic dunes have a convex nose which migrates downwind. They are longer and narrower than barchans and are always associated with blowouts.

2. Loess plain:

• Loess plain is composed of yellowish soil particles that are blown by the wind from the deserts and deposited elsewhere.
• The loess plain contains particles that are very fine textured and rich in quartz silt, clay and carbonate minerals.
• The soil particles do not have any similarity with the rocks and soil present in the region where they have been deposited.

3. Ripple marks:

These are wave-like small-scale depositional features formed by wind action.

They can be of two type:

1. Transverse ripples
2. Longitudinal ripples

Question 55.  Write about the processes of wind action in a desert in the desert.
Answer:

The processes of wind action in a desert in the desert:

The work of the wind is most prominent in desert regions. Wind performs three actions in desert regions—erosion, transportation and deposition.

 

1. Erosion:

The wind carries out erosion by the following processes—

• Abrasion: The wind carries particles of rocks, pebbles, sand, etc., of different sizes along with it as it blows. These particles collide with the landforms on the earth’s surface and create scratch marks, hollows and furrows. Erosion by this process is called abrasion. Landforms formed due to abrasion are—mushroom rocks, yardang, zeugen, ventifact, dreikantar, etc.
•  Deflation: In the process of deflation, the wind blows away sand and smaller rock particles from one place to another. Landforms formed by deflation are—blowouts, pavements, etc.
• Attrition: The rock fragments, pebbles, etc., present in the blowing wind collide with each other and break into smaller fragments and finally convert into sand particles. The process of this breaking down of rock fragments into fine particles of sand due to their collision with each other is known as attrition.

2. Transportation: Wind transports the broken rock fragments and other finer particles by the following methods—

• Suspension: The small and light particles of sand and dust remain suspended in the air and are thus transported to long distances by wind.
•  Saltation: The medium-sized particles of rock fragments are heavy and cannot be transported in suspension. Even if lifted by the wind, they are carried to shorter distances and dropped on the ground wherever the wind is obstructed.

3. Creeping:

1. The larger particles of rock fragments cannot be lifted by the wind due to their heavy weight. They are dragged along the surface while the wind blows.
2. This method of transportation is known as creeping. deserts. Dune migration is harmful as vast regions of agricultural fields, grazing land, human settlement, etc., are buried under huge heaps of sand.

4. Overgrazing:

• The areas adjacent to the desert receive more rainfall than the desert regions.
• Thus, it leads to the growth of grasslands. In the absence of agricultural activities, the people of the desert region take to cattle rearing.
• Overgrazing of animals on these grasslands turns these adjacent areas also into deserts.

5. Rampant cutting down of trees:

Indiscriminate felling of trees in the areas adjacent to the desert regions, leads to the expansion of deserts.

6. Unscientific methods of cultivation:

• Following unscientific methods of cultivation in the areas adjacent to the deserts affects the fertility of these regions.
• As a result, the adjacent areas are also turned into deserts.

7. Deposition:

• Any hindrance in the form of trees, bushes, rocky boulders, etc., in the path of the blowing wind may affect the velocity of the wind.
• As a result, the sand and broken rocky fragments being carried to distances are dropped wherever they are obstructed. These sand accumulations grow in dimension and form several depositional features.

Example: Various dunes, loess plains, etc.

Question 56. Why are the deserts of the world facing severe expansion? Suggest remedial measures to prevent this.
Answer:

At present, the deserts of the world are facing severe expansion.

 

The reasons leading to such an event are as follows—

• Migration of dunes: Migration or shifting of sand dunes causes the expansion of deserts. Dune migration is harmful as vast regions of agricultural fields, grazing land, human settlement, etc., are buried under huge heaps of sand.
• Overgrazing: The areas adjacent to the desert receive more rainfall than the desert regions. Thus, it leads to the growth of grasslands. In the absence of agricultural activities, the people of the desert region take to cattle rearing. Overgrazing of animals on these grasslands turns these adjacent areas also into deserts.
• Rampant cutting down of trees: Indiscriminate felling of trees in the areas adjacent to the desert regions, leads to the expansion of deserts.
• Unscientific methods of cultivation: Following unscientific methods of cultivation in the areas adjacent to the deserts affects the fertility of these regions. As a result, the adjacent areas are also turned into deserts.
• Drought: Areas adjacent to the deserts when affected by frequent droughts, turn into deserts. The water table in these regions is severely lowered and the vegetation also stands affected.
• Global warming: Worldwide increase of temperature due to global warming has affected the temperature, amount of rainfall received, etc., of the regions adjacent to the desert. Decreased amounts of rainfall received and high temperatures are turning the adjacent areas into a desert.

Measures to prevent the expansion of deserts are as follows—

• Afforestation: Planting of trees suitable to the desert environment along the margins of the desert and in the areas adjacent to the desert. to high wind speed, sand being continuously removed from a place creates several small and big hollows or depressions on the ground. These are called deflation hollows or blowouts. In Rajasthan, they are locally known as Dhand.
• Controlled grazing: Overgrazing should be checked in the areas adjacent to the deserts.
• Other sources of fuel: The use of a wood source of fuel should be reduced. Alternative sources of fuel should be looked at regions drought-resistant crops should be grown using modern methods of irrigation.
•  Conservation and judicious use of water: Rainwater harvesting should be extensively practised in the areas adjacent to the desert to mitigate the problem of water shortage. Judicious use of water should also be promoted.

Question 57.  Write down the characteristics of Barchans.
Answer:

The dunes formed transverse to the direction of the blowing wind in the shape of a crescent, is known as a barchan.

Characteristics: The characteristics of barchans are listed below—

The windward slope of the barchan is gentle and convex while the leeward slope is steep and concave.

• The edges of the barchan look like two horns on either side of the crescent.
• Barkhans are usually 15-30m high. Some barkhans may be as high as 200m.
• 4A number of barkhans may develop like a chain in plain regions in the desert. However, they are all temporary and may shift with the change in wind direction.
• Barchans advance on a regular basis at a constant rate when the sand supply is adequate.

Question 58.  Write the characteristics of seif dunes.
Answer:

The long, narrow sand dunes formed parallel to the direction of the wind in a desert region, are called seif dunes. another place

• Characteristics:
  
  Seif dunes can be a few kilometres long and a few hundred metres high.
•  A number of seif dunes may be formed parallel to each other.
• Sometimes, due to very speedy winds, the middle portion of the barchans may get eroded or blown away, and the horns at the edges of the barchans may get transformed into seif dunes.
•  The gap between two adjacent seif dunes is a called corridor. The wind blows at a great speed through these corridors.
•  The top of the seif dunes are sharp and are like saw teeth.

Question 59.  What is a loess plain?
Answer:

Loess plain:

• The yellowish fine sandy particles blown off from the desert regions and deposited elsewhere are known as loess.
• The particles of loess are fine textured and rich in quartz silt, clay and carbonate minerals.
• The fine textured soil particles are blown away from the deserts and the outwash plains and deposited at distant regions, forming a new landform known as a loess plain.

 

 

Example:

• In central Asia, every year, a heavy amount of sandy soil is eroded from the Gobi desert by the northeast monsoon winds.
• They are deposited in the Hwang Ho river valley of northern China.
• This Loess plains formed deposition of sand Plains formed by the deposition of silt in the river basin of River Hwang Ho form a loess plain.
• The depth of the plainland thus formed is 30-200m.

Examples of other loess plains arethe loess plain formed in the southern region of Israel by blowing off the soil from the Sahara desert region of Africa; the loess plain formed in the Mississippi-Missourie River in the USA, etc.

Question 60.  Differentiate between yardang and barchan.
Answer:

The differences between yardang and barchan are as follows-

The landforms formed by the deflation of wind are—

1. Deflation hollows:

• In desert regions, due to high wind speed, continuously removed from a place creates depressions on the ground.
• These are called deflation hollows or blowouts. In Rajasthan, they are locally known as Dhand.

2. Oasis:

• At times the depressions formed due to the deflation action of the wind become their depth reach so deep that As a result, the underground water table.
• Sand over there becomes due to the presence of water, few trees and little moisture and plants grow around the region. Such a landscape is known as an oasis.

 

3. Desert Pavements:

• These are extensive stretches of stony surfaces formed in the desert due to the deflation of the wind.
• Pavements consist of angular or rounded rocky fragments in a matrix of finer sand, silt and clay-sized materials.
• They are locally known by various names in various places. In the Sahara desert, they are known as reg or hammada.

Question 61. Why is the action of wind also active in the coastal regions?
Answer:

The action of wind is highly active in the coastal regions because—

• Extensive coastline: The sea breeze blowing over the open seas come towards the land and blow away the sand from the coast. Thus, the open and extensive coastline assist in the erosional and depositional works of the wind.
• Sea waves: The sea waves splash against the coast continuously, and tend to break the rocks and stones into tiny particles, that can be easily blown away by the wind.
• Deposition of sand: The sand present along the coast can be blown away, carried and deposited elsewhere when the winds are obstructed and lose speed. These landforms are called sand dunes. Example—Such dunes can be seen in the Digha and Contai regions of West Bengal.
• Desert Pavements: These are extensive stretches of stony surfaces formed in the desert due to the deflation of the wind. Pavements consist of angular or rounded rocky fragments in a matrix of finer sand, silt and clay-sized materials. They are locally known by various names in various places. In the Sahara desert, they are known as reg or hammada.

Question 62.  Differentiate between barchans and seif dunes. Or, State three”Seifseif dune” dunes. and “Barkhan”.
Answer:

The differences between barchans and seif dunes are as follows-

Question 63.  Differentiate between pediment and bajada.
Answer:

The differences between pediment and bajada are as follows—

Question 64.  Differentiate between monadnocks and inselbergs.
Answer:

The differences between monadnocks and inselbergs are as follows—

Question 65.  How are crevasses and bergschrunds formed?
Answer:

In high mountainous regions, where heavy snowfall occurs, the ice gets compacted gradually and gives rise to glaciers. Several erosional and depositional features are formed in glaciers.

Bergschrund:

• At the source of the glacier, apart from the headwall of the corrie as the glacier begins to flow.
• This creates a long, narrow and deep fault or trench near the wall of the corrie in the snow. This is known as the bergschrund.

Crevasses:

• As the glacier advances, it crosses many types of slopes on its way. This may create several cracks on the surface of the glacier which are comparatively shallow.
• These are known as crevasses. Both bergschrunds and crevasses remain covered with a thin film of fresh snow. Thus, they can be of great danger to mountaineers.

 

WBBSE Chapter 1 Exogenetic Processes And Resultant Land Forms Short Question And Answers

Question 1. What is the snowline?
Answer:

Exogenetic processes landforms. Snowline:

• Huge snowfall occurs in high altitudes as well as polar regions
• The imaginary line above which the snow never melts totally or below which the snow starts melting is called the snowline.
• Snowline marks the beginning of the permafrost region
• . In low or middle latitudes, the snowline may exist j at S000-6000 m altitude But in polar, regions, it lies at the sea level itself.

Question 2. Classify the glaciers
Answer:

Glaciers can be generally classified into two categories —

1. mountain or valley glaciers and
2. continental glaciers H W. Ahlmann further classified glaciers into 3 broad categories and 11 subtypes based on their thermal and morphological characteristics

The three broad categories are-

1.  Mountain or valley glaciers
2. Continental glaciers,
3. Piedmont glaciers

Question 3. What Is a glacial erratic?
Answer:

Glacial erratic:

In a glacial region, when big rocks are carried too far away distances along with the snow and are deposited there after the glacier melts, the rocks are known as glacial erratics. These rocks are found to have no similarity with the local rocks. Example—Glacial erratics are seen in the high mountainous regions of Pahelgaon in Kashmir.

Question 4. What is a glacier? Name the glaciers that are sources of the river Ganga and Yamuna.
Answer:

Glacier:

Aglacierisamassorriveroficemovingslowly under the impact of gravity. In high altitudes and polar regions, where heavy snowfall occurs, glaciers are formed due to the accumulation of snow above the snowline. The river Ganga rises from the Gangotri glacier and the river Yamuna rises from the Yamunotri glacier.

Question 5. What do you mean by ‘basket of eggs topography’?
Answer:

Basket of eggs topography:

When the rocks, pebbles, sand and clay brought down by the glacier get deposited on the lowland like inverted boats, the topography looks like a number of eggs spread over the land. These are known as drumlins and the topography is known as ‘basket of eggs topography’. Example-Such groups of drumlins are seen in Ireland and Scotland.

Question 6. What do you mean by ice sheet?
Answer:

Ice sheet:

Glaciers are classified into valley glaciers, piedmont glaciers and continental glaciers. Out of these, the continental glaciers are in fact extensive ice sheets. In the polar regions, vast areas are covered with thick layers of ice like a sheet or cover. Thus, the area known as a narrow wall between them is known as an arete. Aretes are sharpened peaks resembling the shape of saw teeth

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 7. What are paternoster lakes?
Answer:

Paternoster lakes:

In high mountainous areas, the glacial valleys seem to develop a number of steps or stairs through the processes of abrasion or plucking. Further, several depressions or hollows are created on these steps or stairs due to glacial erosion. These depressions later get filled with water when the glacier melts. These are known as paternoster lakes.

Question 8. What are knobs and kettles?
Answer:

Knobs: The rocks and pebbles brought down by glacial erosion flow down along with the rivers and spread on the outwash plains. If these materials accumulate like small domes on the plainlands, they are called knobs. Kettles: The big chunks of ice that flow down with the glacier-melt rivers, spread on the outwash plains and create hollows or depressions. These are called kettles. The hollows get filled with water as the ice chunks melt, and thus form kettle lakes.

Example:  ‘Knob and Kettle’ topography is seen in many regions in northern Europe.

Question 9. What is the speed of glaciers?
Answer:

Speed of glaciers:

The glaciers move very slowly. The speed of the glaciers depends upon the slope of the land, the volume of ice, seasonal variations, gravitational pull, etc. Example—The glaciers of the Alps mountains move at an average speed of 5.5 cm per day. The Himalayan glaciers move at a speed of 2.5 7.5cm per day.

Question 10. Why does the end of a glacier look like a tongue?
Answer:

In a valley glacier, the middle part of the body of ice moves forward faster as it experiences friction solely from the valley base. On the other hand, the sides of the glacier experience friction from the base as well as the valley walls. Thus, the rate of movement of glacial ice decreases from the centre towards the edge. This causes the end
of the glacier to look like a tongue. This is also known as glacial snout.

Question 11. What is firn?
Answer:

Firn:

In cold regions, where temperatures drop below the freezing point, snowfall occurs instead of rainfall. The snow falls like the feathers of birds and spread over the ground to form an ice field. An increased volume of snow gets compacted under the pressure of the overlying snow. This partially compacted granular snow is known as firn, which is the intermediate stage between snow and glacial ice.

Question 12. What are Roche mountaineers?
Answer:

Roche mountaineers:

In a mountainous region, due to erosional works of glaciers, large asymmetrical domes with smooth and steep walls may be formed. These landforms are known as Roche mountaineers. Example—Several Roche mountaineers are seen in the glaciated valleys of the Kashmir Himalayas.

Question 13. Why is the degradation process called a destructive process?
Answer:

Degradation is the process by which the higher landforms are lowered by erosion, mass wasting and denudation so as to attain an equilibrium position or a graded profile. Since the original landforms are eroded and lowered by the process of degradation, it is considered a destructive process.

Question 14. Why is vertical erosion or downcutting of river valleys in the upper course more prominent compared to lateral erosion or side cutting?
Answer:

The level of downcutting or vertical erosion of river valleys in the upper course is more prominent compared to side cutting or lateral erosion because the river flows over a steep slope in the upper course, hence having high velocity. Also, the river carries a huge amount of rocks and pebbles in this stage, which act as tools of erosion. Thus, the valleys are deepened due to abrasion by the tools of erosion and the force of the flowing water.

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 15. Why are islands and sand bars created in the middle and lower course of a river?
Answer:

Islands and sand bars are formed in the middle and lower course of the river because of the following reasons—

1. The speed of the river reduces in the middle course as it leaves the mountainous region and enters the plains. Owing to the gentle slope of the land and increased bed load the carrying capacity of the river reduces considerably.
2. Depositions start occurring on the river bed. As more and more depositions occur, the sand bars grow bigger in size and rise out of the water as islands

Question 16. What do you mean by a river?
Answer:

River:

A naturally flowing body of water from the uplands to the lowlands under the gravitational force following the slope is known as a river. It originates in the mountains, hills or plateaus and drains into seas, lakes or other water bodies. A river may be both snow-fed and rain-fed. E.g. rivers Ganga, Brahmaputra, Yamuna, etc.

Exogenetic processes landforms.

Question  17. What do you mean by tributaries and distributaries? Give examples.
Answer:
Tributaries:

The smaller streams of water from the nearby areas that join the main river are called tributaries. Tributaries contribute their water as well as eroded materials to the main flow. E.g. Yamuna is the most important tributary of the river Ganga.

Distributaries:

The small streams branching out from the main river near its mouth in order to distribute its excessive bedload are called distributaries. The load deposited by the distributaries over a vast region from the delta, e.g. Bhagirathi-Hooghli is an important distributary of the river Ganga.

Question 18.  What is an ideal river? Give example.
Answer:

Ideal river:

The river which exhibits all three courses, i.e., the upper, middle, and lower courses prominently is called an ideal river. The river generally erodes in the upper or mountain course, transports in the middle course and deposits in the lower or delta course. The middle and the lower courses are spread over vast areas. An ideal river doesn’t change its course frequently. For example—River Ganga is an ideal river.

Question 19.  How can the course of a river be divided based on the work done?
Answer:

A river performs three activities right from its source to its mouth. The river course can be divided into three parts based on its work. They are as follows—

1. Upper course, marked mostly by the erosional work of the river.
2. Middle course, marked mostly by the transportation work of the river.
3. Lower course, marked mostly by the depositional work of the river.

Question 20. What is the sixth power law?
Answer:

Sixth power law:

The velocity of the stream(river) is one of the major factors on which its carrying or transportation capacity depends. A law to establish their relationship is known as the sixth power law, propounded by G.K. Gilbert. It states that the transportation power of the streams is proportional to the sixth power of its velocity. In other words, if the stream velocity is doubled, the transportation power of the stream increases 64 times. This law can be expressed in the following manner— Transportation power a (stream velocity)

Question 21. What is a water divide?
Answer:

Water divide:

The elevated land acting as a boundary between two river systems is known as a water divide. The water flowing from each side of the water divide flows into each separate body of water. The height of the water divide ranges from a slight elevation on plain land to a crest on a mountain range.

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 22. What is a catchment area?
Answer:

Catchment area:

A catchment area or a drainage basin is an entire area that collects rainwater and contributes it to a channel. The shape of a drainage basin determines how rapidly will the run-off reach the main river and the outlet. In the case of circular basins, the run-off reaches quickly as compared to the elongated basins.

Question 23. What is a river valley?
Answer. 

River valley:

The valley carved out by the river due to excessive downcutting and side-cutting along its course is known as a river valley. The shape and dimension of such valleys vary in each course of the river. V-shaped valleys are formed by the river in its youth stage or upper course while flat valleys are formed when the river reaches its mature stage in its middle course.

Question 24. What are gorges?
Answer:

Gorges:

The narrow steep-sided valleys formed in the mountainous regions due to heavy downcutting by the rivers are known as gorges. These valleys are V-shaped valleys. Here, vertical erosion by the rivers is more prevalent than lateral erosion. Example-Kali Gandaki gorge is a famous gorge in the Himalayas.

Question 25. What are potholes?
Answer:

Potholes:

In the upper course of the river, holes and depressions formed in the beds of the river valleys by the rock fragments and boulders brought down by the rivers are called potholes. Potholes are formed when the rocks get caught in the whirling water, moving in a circular manner and drilling the rocky beds of the valleys to form small holes. These holes gradually become bigger by the repetition of the same mechanism.

Question 26. What are meanders?
Answer:

Meanders:

The bends in the longitudinal course of the river are called meanders. Meanders have been named after the River Meander in Turkey because it flows through several bends. Once the river emerges onto the plains it loses speed due to the gentle slope of the land.

The slightest obstruction in the course forces the river to flow through various bends. Each of these bends has two types of slope. The side where the river strikes have a concave slope and are subjected to severe erosion. The other side is characterised by a convex slope where all the eroded materials are deposited. Thus, meanders are a result of both erosion and deposition.

Exogenetic processes landforms.

Question 27.  What are interlocking spurs?
Answer:

Interlocking spurs:

In a mountainous region, the mountain ridges obstruct the flow of the river in such a way that the river has to erode the foothills and take frequent turns in order to avoid the ridges. From a distance, it appears that the ridges have been interwoven and the river has disappeared into the ridges. Such a series of mountain ridges are known as interlocking spurs.

Question 28. What is a cascade?
Answer:

Cascade:

A series of step-like waterfalls that originate when the river flows over an area with alternating bands of hard and soft rock beds is known as a cascade.

Example: Jonha waterfalls in Ranchi, Jharkhand

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 29.  What are endogenetic forces?
Answer:

Endogenetic forces:

The forces that act from within the earth are called endogenetic forces. These forces cause two types of movement in the earth, namely, vertical movement and horizontal movement. These movements give birth to various relief features such as plateaus, plains, lakes, folds, faults, etc. Volcanic eruptions and earthquakes are also a result of endogenetic forces.

Question 30.  What are exogenetic forces?
Answer:

Exogenetic forces:

The forces which act on the surface of the earth externally and cause changes in landforms, are called exogenetic forces. These forces are also known as denudational forces. Exogenetic forces are constantly engaged in the destruction of relief features which have been formed due to the endogenetic forces. Rivers, glaciers, winds, underground water, and sea waves, are some exogenetic forces that work to change the landforms on the earth’s surface.

Question 31.  What do you mean by gradation?
Answer:

Gradation:

The process of acquiring a smooth and graded profile of landform that lies in equilibrium is called gradation. Gradation includes three processes. The higher landforms are eroded and smoothened in the first phase. In the second phase, the eroded materials are transported by the agents of erosion. In the third phase, the eroded materials are deposited in lowlands or depressions to obtain a graded profile. Thus, gradation helps to eliminate the vertical irregularities of relief on the surface of the earth.

Question 32.  What is aggradation?
Answer:

Aggradation:

The process of increasing the height of a landform by deposition of materials eroded from elsewhere, is known as aggradation. It is a constructive process. Aggradation leads to the formation of alluvial fans and cones, flood plains, etc.

Question 33.  Mention a few instances in which humans and animals act as agents of erosion.
Answer:

At times, human beings and animals also act as active agents of erosion. Mining, construction and agricultural activities cause widespread localised erosion. Burrowing animals such as rabbits, and beavers also act as agents of erosion.

Question 34. What are peneplains?
Answer:

Peneplains:

The featureless plains dotted with small undulations formed at the end of the cycle of erosion by rivers are known as peneplains. The river erodes the high landforms over a considerable period of time and lowers them. The soft rocks are eroded away faster and the hard rocks stand out on the surface as they are eroded less. These hard rocks standing out as highlands on a plain surface are known as monadnocks. E.g.-The Chotanagpur region is a peneplain, and the Pareshnath and Panchet hills lie as monadnocks.

Question 35.  What is the middle course of a river?
Answer:

The middle course of a river:

The river emerges onto the plains from its mountainous or upper course and henceforth this course of the river on the plains is known as its middle course. All along this course, the speed of the river reduces comparatively but the volume of the water carried decreases. Transportation of the eroded materials from the upper course is the main activity of the river in this course. Deposition of the eroded materials is also partially seen along this course. Example-The course of the river Ganga between Haridwar and Rajmahal hills is its middle course.

Question 36. Which is the lower course or delta course of a river?
Answer:

The course of the river flowing through the plains when reaches its mouth is known as its lower course. The speed of the river in this course is vastly reduced due to the gentle slope of the land. The flow also becomes sluggish due to the huge amount of sediment that is carried with the water as a bed load. This leads to the deposition of the sediments near the mouth forming deltas. Example-The portion of the river Ganga, lying between Rajmahal hills to the mouth in the Bay of Bengal is known as the lower course of the river.

Exogenetic processes landforms.

Question 37. What is Plunge Pool?
Answer:

Plunge Pool:

In mountainous regions, waterfalls are created where the river drops from a considerable height with great velocity. Small depressions or hollows known as potholes are created at the base of the waterfalls due to the pounding of rock fragments brought down by the water. These potholes gradually grow bigger in size to form Plunge Pools.

Question 38. Why is the Lohachara island submerging?
Answer:

The Lohachara island at the mouth of the river Hooghly is gradually submerging because—

1. The sea level is rising.
2. Severe cyclonic storms are hitting the area frequently.
3. The mangrove forests are being cut down and thus the coasts are being exposed to erosion.

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 39.  What do you know about South Talpatti island?
Answer:

South Talpatti island:

The South Talpatti island also known as New Moore island existed 2 km away from the mouth of the river Hariyabhanga in the Sunderbans. The cardinal location of the island was 21°37’00″N and 89°08’30” S. The island emerged in the aftermath of the Bhola cyclone in 1970. According to satellite images, the island was about 2500 sq. km in area. The island is currently submerged due to the rise in the sea level as reasoned by scientists.

Question 40.  What is the current condition of Ghoramara island?
Answer:

The current condition of Ghoramara island:

The Ghoramara island lies 92 km south of Kolkata, north of the Sagar islands at the mouth of river Hooghly and east of the mouth of river Haldi in the Bay of Bengal. This is an island in the Sundarban region. In 1951, the size of the island was 38.23sq. km, but by 2011, the size reduced to a mere 4.37sq.km. Experts predict that the island will totally disappear due to submergence in the near future.

Question 41.  What do you mean by rejuvenation?
Answer:

Rejuvenation:

Rejuvenation means acceleration of the erosive work of the rivers due to various factors. This lengthens the period for the cycle of erosion of the rivers. A river may be rejuvenated due to earth movements that cause upliftment or depression of land, substantial fall in the sea level, river capture, etc. Landforms created due to the rejuvenation of rivers include knick points, valley-in-valley topography, incised meanders, paired terraces, etc.

Question 42. What are wadis?
Answer:

Wadis:

The small, shallow dry river valleys found in the deserts are called wadis. The wadis remain dry for most of the time and get filled at times of sudden rain in the desert. They often shift from one position to another or get lost in the sand.

Example:  Wadi Al-Batin of Saudi Arabia is a famous wadi.

Question 43. What do you mean by a pediment?
Answer:

Pediment:

In desert regions, the winds are the strongest agent of erosion. The small rocks, pebbles, sand particles etc., that blow with the wind help in eroding large boulders or mountains to low landforms. A pediment is a plain formed at the foothills of mountains in a desert by the joint action of erosion and deposition by the wind as well as flowing water. It remains covered with rocks and boulders.

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 44. What are dunes?
Answer:

Dunes:

In deserts, the winds are very strong and can lift and carry large amounts of sand as they blow. But if the winds are obstructed by trees, rocks, boulders, bushes, hillocks, etc., they lose speed and drop the sand at the place of obstruction. Thus, the sand gets accumulated as high dumps over long stretches of land. These landforms are known as sand dunes. Dunes also form due to the presence of a dominant direction in which the wind blows.

Question 45. What is a barchan?
Answer:

Barchan:

The barchan is a transfer sand dune that is found in the desert region. It stands across the direction of the wind. It looks like a crescent moon. The middle part of the barchan can be 15-30m high. It has two horns on either side which move forward as the wind blows

Question 46. What is a garage?
Answer:

Garage:

In a desert region, the wind is the most active agent of erosion. The wind erodes mainly by the process of abrasion, where the rocks and pebbles carried by the wind collide against the lower parts or base of a high boulder or a hill. The soft rocks at the base get eroded faster and the hard rocks on the top remain as it is. Thus, the landform develops a narrow base and a broad top. This looks like a mushroom and thus is known as a mushroom rock. Such mushroom rocks are known as gara in the Sahara region.

Question 47. What is loess? Or, Define Loess.
Answer:

Loess:

Loess are the yellowish soil particles that are blown by the wind from the deserts and deposited elsewhere. Loess contains particles that are very fine textured and rich in quartz silt, clay and carbonate minerals. The soil particles do not have any similarity with the rocks and soil present in the region where they have been deposited. The plains formed of the loess deposits are called loess plains.

Question 48. What is an oasis?
Answer:

Oasis:

In desert regions, a huge depression may be created due to the blowing away of sand by the wind regularly. The depression becomes so deep that the surface of the region reaches the level of the underground water table. Thus, water is easily available here, and the soil remains moist. This region is known as the oasis, as the availability of water helps in the growth of trees around the depression and makes this region look green. An oasis is like a garden in the desert region.

Question 49. What are ventifact and dreikanter?
Answer:

Ventifact: In a desert region, if the wind blows from one direction, the large rocks are polished on one side (the side facing the wind) by the process of abrasion, while the other sides remain uneven and rough. Such a rock is known as a ventifact.

Dreikanter: If the wind blows from different directions, all the faces of the rocks standing out are polished by the process of abrasion. Thus, a landform with three polished faces is formed. This is known as dreikanter.

Question 50. What are seif dunes?
Answer:

Seif dunes:

‘Seif’ means sword in Arabic. The long and narrow dunes like swords formed in the deserts are called seif dunes.
The seif dunes are formed in sandy deserts parallel to the direction of the wind. These are practically the longitudinal dunes. According to scientist Bagnold, the barchans in the desert region get gradually converted to seif dunes.

Question 51. What are blowouts or deflation hollows? Or, How are the “deflation hollows” formed?
Answer:

Blowouts or deflation hollows are sandy depressions found in desert regions. They are formed by the removal of sand from a region by the wind. They are commonly found in arid regions or coastal regions where there is the sufficient sand cover. Example—Qattara Depression, Egypt.

Exogenetic processes landforms.

Question 52. What do you mean by playa lakes?
Answer:

Playa lakes:

The saltwater lakes found in desert regions are called playa lakes. They are known as ‘hands’ in Rajasthan and ‘shafts’ in Sahara. The ephemeral streams that originate from the surrounding mountains drain into these lakes. The non-perennial rivers of the desert region may also drain into these playa lakes.

Question 53. What is a bajada?
Answer:

Bajada:

The gently sloping plain land lying between the pediment and the playa in a desert region is called a bajada. It may be formed at the foothills of mountains by the accumulation of clay, silt and pebbles. The alluvial cones formed at the foothills of mountains in a fluvial aeolian environment may join with each other and form a bajada.

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 54. Why does abrasion occur at a height of a few metres above the earth’s surface?
Answer:

Abrasion is the process in which the rock pieces, pebbles and sand blown by the wind rub against or collide against the rocky hills or walls on the earth’s surface and thus erode them. Abrasion occurs only till a few metres above the ground because the large rock pieces cannot be lifted too high above the ground by the winds. The presence of erosive tools carried by the wind is maximum at the lower columns of air than at a height.

Question 55. What are star dunes?
Answer:

Star dunes:

In desert regions, winds blow from different directions during different times of the year. Thus, dunes are formed in different directions. Star dunes are formed by variable winds. They grow vertically and do not migrate laterally. A star dune has multiple slip faces, a central peak and three or more arms extending radially.

Question 56. What do you mean by Agassi?
Answer:

Agassi:

The seif dunes lie parallel to one another and the gap or passage between two adjacent seif dunes is called a corridor. These corridors are devoid of sand and lie as pavements or vast stony plains in the desert. These are called reg. Such reg or corridors between parallel dunes are known as gassy in Sahara, Africa. These corridors are used as caravan paths for travelling through the deserts.

Question 57. What do you mean by erg?
Answer:

Erg:

The vast stretches in the desert made up of sand accumulations are known as ergs. Ergs are formed where the wind is most active and the amount of sand present is huge. These depressions of wind accumulations were formerly filled with alluvium.

Question 58. Name some deserts of the mid-latitudes.
Answer:

Some deserts of the mid-latitudes are— Gobi, Taklamakan and the desert of Turkestan in Asia, the Colorado desert in North America, etc. The number of deserts in mid-latitudes is more than the number of deserts in low latitudes.

Question 59. Name some deserts of the low latitudes.
Answer:

The low-latitude deserts are found within 20°-30° latitudes in both hemispheres. These deserts have developed on the western margins of the continents. E.g.— Sahara, and Kalahari in Africa; the Arabian desert, the Baluchistan desert and Thar desert in Asia; Soneran in North America, the Great Australian desert in Australia, etc.

Question 60. What is adobe?
Answer:

Adobe:

In North America, loess deposits are found in the valleys of the Mississippi and Missouri rivers. Scientists believe that this landform had been formed in the Pleistocene Age when sand from the moraines and outwash plains was blown off and deposited here. These loess deposits are known as adobe in North America. Loess is extensively found in Nebraska, Illinois, Iowa, etc.

Question 61.  Why do valleys rivers while carving glaciers out T carve or out’V’ ‘U’ shaped valleys?
Answer:

Case Studies on Exogenetic Landforms

• The rivers have great speed in the mountainous region.
• The intensity of downcutting is more than the intensity of side cutting. regions the valley carved out are ‘I’ shaped and while flowing through the wet regions the shape of the valleys resembles the letter V.
• In the case of glaciers, the intensity of side-cutting of valleys is similar to that of downcutting. Rocks are broken and removed by the process of plucking and abrasion.
• Thus, the shape of the valley resembles the letter ‘U’.

WBBSE Chapter 1Exogenetic Processes Landforms.

Question 62. Mention the importance of glaciers as a source of sweet and fresh drinking water.
Answer:

• A glacier is not only a frozen river of ice but also influences the landform and climate. the environment of the glacial region.
• It can be considered as a reserve for freshwater pres in the frozen form. About 97.20% of the water present on the earth’s surface is salty and unfit for use. The rest 2.80% of the water is fresh.
• Out of this share, about 0.0001% of the water flows through rivers, 0.9999% lies as underground water, and 1% remains frozen as ice.
• This means that about 75% of usable fresh water is trapped in the glaciers. Out of this about 90% or more lie in Antarctica.
• Rivers like Ganga, Yamuna, Indus and Brahmaputra rise from the glaciers. Thus, the glaciers in the high mountains are important in being reserves of freshwater in frozen form.

Question 63.  Why are the roches moutonnees smooth on one side and rough on the other?
Answer:

• In a glaciated region, if a large boulder, or rock comes in the way of the glacier, the side over which the glacier moves forward is smoothened and polished by the process of abrasion.
• The opposite side over which the glacier descends is plucked and eroded and weathered.
• Thus, one slope of the Roches moutonnees is smooth while the opposite side is rough, uneven and plucked.

Question 64.  How are glacial stairways formed?
Answer:

When the glaciers descend from very high mountains into valleys, they develop steps or stairs along the walls of the valleys through the processes of abrasion and plucking. The steps may develop due to unequal distribution of load in the glacier or alternate alignment of hard and soft rock beds. These steps are known as glacial stairways.

Question 65. What do you mean by abrasion?
Answer:

Abrasion:

Abrasion or corrasion is a type of erosion. The natural agents of erosion like rivers, glaciers and wind bring down rock fragments, pebbles, sand and stones that rub against the rock beds on the surface of the earth. This is known as the process of abrasion. Thus, the surface is polished and eroded fast by the removal of loosened materials.

Question 66. What are eskers?
Answer:

Eskers:

Eskers are depositional landforms found in the lowlands or foothills of mountains or valley glaciers. When the debris (rocks, pebbles, stone, etc.) brought down by glaciers gets deposited like low-lying ridges (about 15 m in height) with branches, they are called eskers.

Exogenetic processes landforms.

Question 67. Where is the erosional action of wind most predominant?
Answer:

In arid regions of the world where the rainfall received is less than 25cm, growth of natural vegetation is negligible or almost absent the erosional action of the wind is most predominant. The land surface remains open and uncovered. There are almost no obstructions to the blowing wind. Hence the winds blow at a great speed. Also, the high diurnal range of temperature leads to the disintegration of rocks. These rock fragments are carried with the wind further eroding the landscape by the process of abrasion.

Question 68. How is sand formed in the deserts?
Answer:

In the desert regions, the diurnal and annual ranges of temperature are very high. This enhances weathering by mechanical methods, where the large rocks are gradually broken down into small rock fragments. Also, abrasion of rocks leads to further breakdown of rocks into sand particles. Lack of rainfall helps to speed up the whole process. Thus, sand is formed in the deserts.

Question 46. What do you mean by global warming?
Answer:

Global warming:

• The phenomenon of increase of the earth’s temperature gradually is known as global warming. The earth receives solar radiation through short waves and gets heated.
• This heat is transferred through the atmosphere by long waves and finally released into outer space. But excessive emission of greenhouse gases like CFCs, carbon dioxide, etc. creates a transparent film of gases that prevent the escape of these long waves.
• Thus, heat is retained in the atmosphere and the result is global warming. Radiated energy (longwave terrestrial radiation) into space is partly absorbed and partly reemitted by  the earth

Question 47. What are horse latitudes?
Answer:

Horse latitudes

In both the northern and southern hemispheres, at 30°-35°C latitudes, high pressure prevails due to the sinking of heavy and cold air over this region. Hence, there is no movement of wind felt in this region, and a calm condition prevails.

Horse latitude:

• In the early days, the ships that used to sail from Europe to North America and West Indian islands with horses, used to lose their speed while crossing this calm region.
• Then, the sailors used to throw away some horses into the sea in order to reduce weight and consumption of food and water.
• This helped the ships to sail forward with the help of whatever little wind blowing. Due to this incident, the sub-tropical calm region between 30° and 35° latitudes came to be known as horse latitudes.

Question 48.  Why do the pressure belts shift at certain times of the year?
Answer:

• On the earth’s surface there are three low f pressure belts and four high-pressure belts. These belts are generally fixed in their locations, but at certain times of the year, they seem to deviate for a few degrees northwards and southwards.
• This is known as the shifting of pressure belts.

Belts shift  Causes:

Due to the revolution of the earth, the sun apparently moves northwards and southwards. Thus, the thermal equator or the heat equator also shifts accordingly.

• When it is summer in the northern hemisphere, the thermal equator and all the pressure belts move 5°-10° towards the north. During winter in the northern hemisphere, the thermal equator as well as all the pressure belts move 5°-10° towards the south.
• Generally, the shifting of pressure belts is more prominent in the lower latitudes than the higher latitudes.

Question 49. What do you mean by cloudiness?
Answer:

Cloudiness

• The amount of cloud cover in the sky is known as cloudiness. An okta is a unit of measurement used to describe the amount of cloud cover at any given location.
• The sky is divided into 8 parts and the amount of cloudiness is measured in terms of how many eights of the sky are covered in cloud. Cloudiness is represented on weather maps with the help of certain symbols.

Question 50.  What is smog? How is it created?
Answer:

Smog

• Smog is the combination of smoke and fog. In large cities and urban centers, the sky remains filled with smoke, carbon particles, and other solid chemical particles that float as aerosols in the air.
• These particles act as the media of condensation. Early in the morning, the atmospheric water vapor condenses on these floating particles and creates a hazy sight.
• The smoke emitted by vehicles and industries adds up to this and reduces visibility even more. This is known as smog. Smog is harmful to health as it contains pollutants coming from vehicles and industries.

Example: Shanghai and Beijing in China, industrial towns and cities in Europe, etc. are affected by dense smog.

Question 51.  How is rainfall measured?
Answer:

Rainfall is measured with the help of a ‘Rain gauge’. The instrument comprises a graduated cylinder, fitted inside a large outer cylinder with a wide funnel on top.

• The instrument is kept in an open area that receives no other source of water apart from the rainfall. After every 24 hours or any fixed interval, the reading is taken to record the amount of rainfall.
• The excess amount of rainwater overflows into the outer cylinder which is poured into another graduated cylinder. This reading is added to the previous one to record the total rainfall.

Question 52.  Why are fog and dew not considered precipitation?
Answer:

In precipitation, the water vapor present in the rising air condenses with a gain in altitude due to cooling. Thus, they come down as rainfall or snowfall.

• Dew is not formed from any rising air that carries water vapor. Due to radiation throughout the night, the air becomes cold and whatever water vapor is present in the lower layers of the air gets condensed on the cold surface of grasses, leaves, rooftops, etc.
• Thus, it is not precipitation.
• Fog is formed when the earth radiates back heat throughout the night, especially in winter. The air adjacent to the earth’s surface also cools down and the water vapor present in the air settles on the dust particles and condenses.
• They form so little droplets that they remain floating in the air, thus reducing visibility.
• As fog is not– dropped from the atmosphere maximum rate of evaporation and decreasing amount towards the earth’s surface, it is not considered precipitation.

Question 53. Where is the Tundra climate found in the world? Mention its characteristics.
Answer:

Tundra climate is found between 65″N- 80°N and 60°S-75°S latitudes. The regions where Tundra climate exists are—The coastal regions of the Arctic Ocean in Canada, Greenland, Europe, and Russia.

Characteristics:

1. The temperature remains below the freezing point for about 8-9 months in a year.
2. The maximum temperature recorded during the summer season is about 10°C.
3. Snowfall is predominant in this region instead of rainfall due to very low temperatures.

Question 54. Where is the steppe climate found in the world? mention its characteristics.
Answer:

Steppe climate is found between 30° latitudes in both the northern and southern hemispheres.

The regions experiencing such climate are:

• Prairie region of North America.
• Pampas region of South America.
• Eurasia.
• Veld of South Africa.
• Downs of Australia.

Characteristics:

• The average summer temperature remains around 16-20°C.
• The average winter temperature remains around 5-8°C.
• The annual range of temperature is quite large.
• The summers are hot and humid, the winters are dry.
• The average annual rainfall varies from 25-75 cm. This helps in the growth of grasslands over extensive areas.
• Snowfall occurs sometimes in winter.
• The grasslands in the southern hemisphere enjoy maritime or moderate climates due to the influence of the oceans.

Question 55. Where is the marine west coast climate experienced In the world? What are its characteristics?
Answer:

The marine west coast climate is found between 40 and 65° latitudes in both the northern and southern hemispheres. The north-western part of Europe (western Norway, Denmark, etc.), a few places in the USA, the southwest coast of Chile, southeast coast of Australia experience such climate.

Characteristics:

• The average summer temperature remains around 16°C.
• The average winter temperature remains around 4°C.
• The general climate is moderate or maritime.
• Rainfall occurs mainly by the influence of westerly winds. The average annual rainfall is about 75-100 cm.
• Sometimes snowfall occurs in winter.

Question 16 Where is China’s type of climate found in the world? What are its characteristics?
Answer:

The China type of climate is found between 20 and 40° latitudes in both northern and southern hemispheres along the eastern parts of the continents.

The regions under this climatic type are—

• Southern and southeastern China.
• Eastern coast of Australia.
• The south-eastern part of the USA.
• South-eastern parts of Brazil, Paraguay, and Uruguay.

Climate found Characteristics:

• Summers are hot and humid and the winters are mild.
• The average summer temperature is around 24-26°C.
• The average winter temperature is around 6.6-10°C.
• Rainfall occurs during summer under the influence of sea breeze.
• The average annual rainfall is 100-150 cm.

Question 56.  Where is a continental climate found in the world? What are its characteristics?
Answer:

The continental climate is found between 30 and 65°N latitudes in the northern hemisphere.

The regions receiving such climate are—

1. Lake region of USA,
2. Russia, Ukraine, and central Europe,
3. Manchuria and Sakhalin islands

Continental climate found Characteristics:

• The average summer temperature remains quite high (20-25°C).
• The average maximum temperature recorded in the winter is 2-5°C.
• The temperature remains below 0°C during most of the days in winter.
• Snowfall occurs during winter. Heavy snowfall occurs for at least 60-80 days a year.
• The average annual rainfall is 50-100 cm.
• The range of average annual temperature is very large.

Question 57. Where is a wet temperate climate found in the world? Mention its characteristics.
Answer:

The wet temperate climate is found in the region between 55 and 65° latitudes in both the northern and southern hemispheres.

The regions that experience this climate are—

1. The northern part of Eurasia, south of the Tundra region.
2. North America, south of the Tundra region.

Temperate climate found Characteristics:

• The summer season lasts for about 3 months when the average temperature remains around 10°C.
• The temperature remains below the freezing point for most of the days in winter.
• The average annual rainfall is about 20-25 cm.
• Most of the rainfall occurs during summer.
• Snowfall occurs during winter.
• The range of temperature between summer and winter is quite large, which shows that the climate is of the extreme continental type.

WBBSE Chapter 2 Atmosphere Short Question And Answers

Question 1. What may happen due to the creation of the ozone hole?
Answer:

• Importance of the ozone layer: The ozone layer protects the earth like an umbrella from the harmful ultraviolet rays of the sun. It saves plant and animal life from decay and diseases.
• The consequence of the ozone hole: The creation of an ozone hole will allow the harmful ultraviolet rays of the sun to enter the earth’s atmosphere. This will cause several diseases like skin cancer, damage of the cornea of the eyes, infertility, skin diseases, death of fishes and other aquatic life, wilting of leaves of plants, etc.

Question 2. Write the effects of depletion of the ozone layer.
Answer:

The effects of depletion of the ozone layer:

The ozone layer is being gradually depleted by CFCs, nitrogen oxide, sulfate compounds, etc.

The effects of ozone layer depletion are—

• On climate: The depletion of the ozone layer allows the harmful ultraviolet rays of the sun to enter the earth’s atmosphere. This causes global warming, which further leads to the depletion of the ozone layer.
• On human beings: The depletion of the ozone layer causes skin cancer and other skin diseases, reduces fertility, damages the cornea of the eyes, etc.
• On ecosystem: The ecosystem is also hampered due to ozone layer depletion. Plants lose productive capacities. Many small animals may get extinct.

Question 3. Why do jet planes fly through the stratosphere?
Answer:

• The jet planes fly through the stratosphere because—
  
  The stratosphere is free of water vapor and weather phenomena like winds, thunderstorms, rainfall, etc. The very fine dust particles present here do not hamper the flying of planes.
• This layer is practically devoid of air and there is very little friction and no disturbances in the atmosphere.
• The presence of jet streams in the tropopause also helps in saving costly aviation fuel because jet streams propel jet planes to fly easily following them.

Question 4. How is the ozone layer contracting?
Answer:

The ozone layer contracting:

• The excessive emission of chlorofluorocarbons, nitrogen oxide, sulfur dioxide, and other greenhouse gases is harming the ozone layer. Big holes have been detected in this layer especially, over the Antarctic region.
• According to scientists, the creation of ozone holes may lead to diseases such as skin cancer, damage to the cornea of the eyes, etc. due to the ultraviolet rays reaching the earth’s surface

Question 5. Why are days very hot and nights very
Answer:

The days are very hot and the nights are very cold in hot desert regions because—

• The clear sky in hot desert regions allows solar radiation to reach the earth’s surface and heat it up fast. Thus, sands present in the desert regions get heated up fast and accordingly heat up the atmosphere. Thus, the temperature rises very high during the daytime.
• After the sun sets, the sands of the deserts radiate back heat very fast. Due to the clear sky, the heat is released into space very fast and the sand cools down. This makes the nights cold in the hot desert regions.

Question 6. Why are cloudless nights cooler than cloudy nights?
Answer:

• The cloud cover of the sky prevents the insolation to reach the earth’s surface during the daytime and terrestrial radiation of the solar energy into space in the afternoon. This makes the days comparatively cooler and the nights comparatively warmer in cloudy conditions.
• On the other hand, if the sky is clear and cloudless, the insolation heats up the atmosphere very much during the daytime and the energy is fully radiated back during the night. Thus, the days seem to be warmer and the nights seem to be cooler.

Question 7. Mention the factors that influence the heat budget of the earth.
Answer:

The amount of solar energy received by the earth, or the heat budget of the earth is maintained by the following factors—

1. Angle of incidence of sun’s rays: The lower latitudes receive perpendicular rays of the sun and the rays become inclined as the latitudes increase. Thus, the equatorial region and lower latitudes receive more heat than the higher latitudes and polar regions.

2. Distance between the earth and the sun: The earth moves around the sun in an elliptical orbit. Hence, sometimes the distance between the sun and the earth decreases and sometimes increases. This affects the amount of heat received by the earth’s surface.

3. Length of day and night: The regions which have longer daytime receive more solar energy than the regions which have longer nights.

Question 8. Mention the different methods of calculating and recording the temperature of a place.
Answer:

The different methods of calculating and recording the temperature of a place

Temperature is recorded by the thermometer. Generally, the Six’s maximum and the minimum thermometer are used to record the maximum and minimum temperatures of the day of a particular place.

This is also used to calculate the—

1. Average daily temperature = Highest temperature of the day + Lowest temperature of the day.
2. Average annual temperature = Total of the monthly average temperatures
3. Range of temperature = Highest temperature – The lowest temperature

Question 9. Why does Mt. Kilimanjaro remain snow-covered even though it is located on the equator? OR, Why does the capital of Ecuador, Quito have a subtropical highland climate?
Answer:

Mt. Kilimanjaro is located on the equator and is 5.9 km in altitude. The average temperature of the equatorial region is 27°C. By the lapse rate, the average temperature of the peak of Mt. Kilimanjaro is 27°C – (6.4°C x 5.9) = -10.76°C. Thus, Mt. Kilimanjaro remains snow-covered throughout the year.

• The capital of Ecuador, Quito is located in the equatorial region at 2.8 km above mean sea level. The average temperature of the equatorial region is 27°C.
• Thus, by the lapse rate, the average temperature of Quito is 27°C – (6.4°C x 2.8) = 9.08°C. Thus, Quito enjoys a sub-tropical highland climate.

Question 10. Why does the water of the Baltic Sea freeze but water around the British Isles does not freeze in spite of both lying along the same latitude?
Answer:

• The latitude at which the British Isles as well as the Baltic Sea lies, makes the region very cold. Thus, it is very natural for water to freeze.
• But the warm Gulf Stream passing along the coast of the British Isles keeps the water warm and prevents it from freezing during winter.
• On the other hand, the Baltic Sea is surrounded by land, and no warm current flows through it. Thus, the water becomes very cold and freezes during winter.

Question 11.  Why do landmasses get heated faster than water bodies?
Answer:

Landmasses get heated faster than water bodies because of the following reasons—

1. The heat received by water bodies is transferred to the depths by the convectional currents. No such convectional currents work on landmasses.
2. The absorption of solar energy is lower over water bodies than landmasses. Thus, landmasses get heated quicker than water bodies.
3. The amount of energy required to heat up per unit volume of water by 1°C is about three times the energy required to heat up per unit volume of landmasses by 1°C. Thus, if the same amount of energy is supplied, landmasses get heated faster than water bodies.
4. Water being transparent, solar energy penetrates up to 200m depth and distributes the heat. Land being opaque, heat gets concentrated on the surface only.

Question 12.  Discuss the causes of global warming.
Answer:

The major causes of global warming are—

1. Excessive use of fossil fuels: The excessive use of fossil fuels in vehicles, industries, and thermal power plants is increasing the level of carbon dioxide in the atmosphere. The gas absorbs much heat and Increases the temperature of the earth.

2. Emission of methane gas: Methane is a greenhouse gas emitted from wetlands, waterlogged rice fields, decaying organic matter, excreta of domestic animals, etc. This plays an important role in increasing the temperature of the earth.

3. Deforestation: Reckless cutting down of trees leads to deforestation. This is gradually increasing the percentage of carbon dioxide in the atmosphere, which is a greenhouse gas. The concentration of carbon dioxide in the atmosphere is increasing the earth’s temperature and causing global warming.

4. Emission of nitrous oxide: The use of nitrogen-rich fertilizers in agriculture, forest fires, etc. emits a huge quantity of nitrous oxide (N20), which leads to global warming.

5. CFC gases: The use of refrigerators, air; conditioners, electronic gadgets, body sprays, cosmetics, etc. increase the use of chlorofluorocarbons (CFCs) which is one of the major causes of global warming.

Question 13. What is El Nino? Discuss its influences.
Answer:

El Nino:

El Nino is a southward-moving warm current of the Pacific Ocean which flows along the western coasts of Peru and Ecuador. El Nino causes a considerable rise in the air temperature of the eastern Pacific Ocean.

Influences or effects:

1. El Nino causes heavy rainfall in the coastal areas of Peru and Ecuador that often leads to flooding.
2. Dry weather persists in the Amazon basin, Central America and Australia. This often causes forest fires.
3. According to climatologists, El Nino also influences the circulation of the monsoon winds. Hence, in the years when El Nino Occurs, India experiences droughts, The desert regions of Chile and Peru experience floods.
4. The warm effect of El Nino kills the coral polyps and other marine creatures.
5. El Nino results in a rise in general temperature and a decrease in rainfall in southeast Asia.

Question 14. What is La Nina? Discuss its influence.
Answer:

La Nina:

The opposite condition of El Nino is known as La Nina. During this time, the surface temperature of the Pacific Ocean in the coastal areas of Peru and Ecuador decreases by 49C or more.

Influence or effects:

1. La Nina causes heavy rainfall along the western coast of the Pacific Ocean.
2. The western coast of South America experiences droughts.
3. Dry weather persists in the USA.
4. Canada experiences chilling cold and heavy snowfall.

Question 15. Why does the atmosphere get heated?
Answer:

The chief source of heat in the atmosphere is the sun. Solar energy reaches the earth’s surface and heats it up. This heat is transmitted into the atmosphere by the processes of conduction, convection, and radiation. Apart from this, the absorption of the ultraviolet rays by the ozone layer in the Stratosphere also heats up the atmosphere considerably.

Question 16. Discuss the characteristics of air temperature as found in different regions of the earth.
Answer:

The characteristics of air temperature in different parts of the earth are as follows—

1. Air is warmest at the equator and coldest at the poles in both the northern and southern hemispheres.
2. The temperature in the equatorial region remains almost the same throughout the year.
3. Although the polar regions remain very cold throughout the year, differences in air temperature between summer and winter can be seen.
4. The revolution of the earth around the sun results in the highest temperature in the northern hemisphere in July and that in the southern hemisphere in January. Reverse conditions are found during winter.
5. Temperature decreases by 6.4°C for every 1000 m rise in altitude. This is known as the normal lapse rate.
6. Winds are warmer along coasts where warm ocean currents flow, and cooler along coasts where cold ocean currents flow.
7. If a warm wind blows over an area, the temperature increases and vice versa.

Question 17. How is air temperature measured?
Answer:

Air temperature measured:

Air temperature is measured by the thermometer in degrees Celsius (°C) and degrees Fahrenheit (°F). The Six’s maximum and the minimum thermometer are used to measure the maximum and minimum temperature of a day. This is used to calculate the diurnal range of temperature, monthly average temperature, monthly range of temperature, and annual range of temperature.

Question 18. What are the ‘thermal zones’ of the earth? Name the different thermal zones on earth.
Answer:

The earth can be divided into different circular belts or zones according to the level of temperature persisting in different parts of the earth. These zones are known as thermal zones of the earth.

Thermal zones: There are five thermal zones on the earth’s surface—

1. Torrid zone — (231/iN- 2334°S),
2. North Temperate zone — (23y2N -661/2°N),
3. South Temperate zone — (2334S -66/4°S),
4. North Frigid zone — (661/2°N-90°N),
5. South Frigid zone — (66/4°S-90°S)

Question 19. Discuss The Causes Of the Formation Of The Torrid Zone.
Answer: 

Location: The region lying between 231/2°N and 231/2°S latitudes across the equator is known as the Torrid zone.

Causes: The angle of incidence of sun’s rays varies between 43° and 90° in this region. Thus, the heat received here is maximum. The sun’s rays traverse a smaller distance in the atmosphere before reaching the earth’s surface. Thus, the loss of heat due to scattering, absorption, and reflection is less. The Torrid zone remains warm throughout the year, and the average temperature is around 27°C.

Question 20. What is the diurnal range of temperature of a place with a maximum temperature of 38°C and a minimum of 26°C?
Answer:

Diurnal Range of temperature = Maximum temperature – Minimum temperature = 38°C- 26°C = 12°C
Therefore, the diurnal range of temperature of the place is 12°C.

Question 21. Calculate the average temperature of Suri if the maximum temperature was 35X and the minimum was 2SX on 12th April 2018.
Answer:

Average temperature Maximum temperature + Minimum temperature/2
=35 +28/2 = 63/2
=31.5

Question 22. Calculate the average annual temperature of Maldah from the following table.

1. 

2. 

Answer: = Average annual temperature total of average monthly /12 = 2888.10/12 =24.01c

Question 23. Why are winter nights colder in Delhi than in Mumbai?
Answer:

The winter nights are colder in Delhi than in Mumbai because of the following reasons—

1. Mumbai is located on the coast of the Arabian Sea. Thus, it enjoys a moderate or maritime climate. Delhi is located far away from the influence of the sea. Thus, it experiences extreme or continental climates.

2. Mumbai is located at 19°04′ N latitude and Delhi is located at 28°42′ N latitude.

• Thus, Delhi is located comparatively northward of Mumbai. The angle of incidence of sun’s rays is slightly more inclined in Delhi than in Mumbai.
• Hence, Mumbai receives more heat than Delhi. During the night, the lesser amount of heat absorbed by Delhi is radiated back faster than that by Mumbai. Thus, nights are warmer in Mumbai than in Delhi.

Question 24. Why is London cooler than Kolkata?
Answer:

London is cooler than Kolkata for the following reasons—

• Kolkata is situated at 22°30′ N latitude and London is situated at 51°30′ N latitude. London because of its location far north of Kolkata receives the sun’s rays at a more inclined angle than Kolkata.
• Hence, the average temperature in London is lower than that of Kolkata. Thus, London is cooler than Kolkata.

Question 25.Why are places in higher altitudes cooler than that in lower altitudes?
Answer:

The causes of places at higher altitudes being cooler are as follows—

1. The amount of water vapor and dust particles in the air decreases with an increase in altitude. Thus, absorption and retention of heat are less.
2. The density of air in higher altitudes is less. The light winds radiate heat quickly and become cool.
3. Effects of conduction, convection, and radiation of heat in higher altitudes are quite less. The temperature remains low due to the normal lapse rate.

Question 26. Mention the main characteristics of the range of temperature.
Answer:

The main characteristics of the range of temperature are—

1. The range of temperature throughout the day, month, or year is lowest at the equator.
2. The range of temperature is highest in higher latitudes.
3. The range of temperature is greater over landmass than on water bodies.

Question 27. What do you mean by ‘Normal Lapse
Answer:

Normal Lapse:

• The earth’s surface gets heated first by the insolation.
• This energy is then transmitted to the atmosphere by the processes of conduction, convection, and radiation.
• Generally, temperature decreases by 6.4°C for every 1000 m or 1 km rise in altitude. This rate of decrease in temperature is known as the normal lapse rate.
• The higher altitudes remain cooler and the high mountains remain snow-capped due to the lapse rate of temperature.

Question 28. Explain the process of transfer of heat by conduction.
Answer:

The process of transfer of heat by conduction:

• Conduction is the mode of heat transfer from one part of a substance to another part within the substance itself or to a different substance that is placed in physical contact. In conduction, there is no noticeable movement of molecules.
• Energy is transferred by the movements of free electrons through vibrations between atoms and molecules.

Example: ln the atmosphere, the lower layers transfer heat to the upper layers by the method of conduction. This occurs best during the daytime.

Question 29. Explain the process of convection in the transfer of heat.
Answer:

The process of convection in the transfer of heat:

The air adjacent to the earth’s surface especially in the equatorial region gets most heated, becomes light and rises. Air from adjacent areas which is cooler and heavier rushes to fill up this vacuum created. This cyclical movement of warm air upward and cooler air downwards and sidewards to fill up the gap is known as convection.

The atmosphere gradually gets heated from below upwards by the physical movement of gas molecules from bottom to top. Convection is mostly seen in the equatorial region due to vertical rays of the sun falling on this region

Question 30. Name the factors responsible for differences in temperature in different parts of the earth.
Answer:

The main factors responsible for differences in temperature in different parts of the earth are—

1. Latitude,
2. Altitude,
3. Length of day and night,
4. Presence of mountains,
5. The slope of the land and
6. Distance from the sea.

Question 31. What do you mean by the greenhouse effect?
Answer:

Greenhouse effect:

The gradual increase of the earth’s temperature due to the presence of certain gases in the atmosphere is known as the greenhouse effect.

The carbon dioxide, methane, and chlorofluorocarbons present in the atmosphere create a transparent envelope in the atmosphere which prevents solar energy from radiating back to space. Thus, the temperature of the earth’s atmosphere gradually increases.

Question 32. Name some greenhouse gases.
Answer:

Some greenhouse gases present in the atmosphere are—

1. Carbon dioxide,
2. Methane,
3. Chlorofluorocarbons,
4. Carbon monoxide,
5. Nitrous oxide,
6. Water vapor, etc. Amongst these, carbon dioxide is the most important greenhouse gas.

Question 33. How does the difference in air pressure generate winds?
Answer:

• Winds are generated primarily due to differences in pressure conditions between two regions. If the ground gets heated too much, the adjacent air also gets heated. This air becomes lighter and tends to rise upward.
• Thus, a vacuum or low-pressure cell is created. Winds from the adjacent cooler regions rush towards this low-pressure region and try to bring a balance in the pressure conditions.
• Thus, winds blow from high-pressure regions to low-pressure regions.

Question 34. List the characteristics of tropical cyclones.
Answer:

The characteristics of tropical cyclones are—

1. The center of the cyclone, where the pressure remains the lowest is called the eye of the cyclone.
2. Generally, clear skies and calm conditions prevail in the eye region of the cyclone.
3. The eye of the cyclone is surrounded by cumulonimbus clouds.
4. Winds rush in from the region around the eye with great speed and cause thunderstorms and rainfall.
5. The cyclones move in an anticlockwise direction in the northern hemisphere and a clockwise direction in the southern hemisphere.

Question 35. Write a short ‘north westers’.
Answer:

‘North westers’

• North ‘westers or Kalbaishakhi is a tropical storm that occurs in India and Bangladesh. In India, the states of West Bengal, Odisha, Bihar, Jharkhand, and Assam come under the influence of northwestern in the summer season.
• This is a sudden wind that causes thunderstorms, rainfall, and sometimes hailstorms.

North westers Causes:

• During the summer season, the day-long heating of the Chotanagpur plateau heats up the adjacent air.
• Thus, warm air rises upwards and creates a low-pressure cell over the rocky plateau region.
• This low-pressure cell is the main cause of drawing winds from the surroundings and forming a tropical storm.
• Usually, the air comes from the north-western direction to fill up the low-pressure region, hence the name ‘northwestern’ (north + western).

North westers Effects:

• The day’s temperature may fall up to 10° C with little rainfall.
• However, rainfall is beneficial for tea, rice, and jute cultivation.

Question 36. What are the causes of planetary winds?
Answer:

The causes of planetary winds

• The general characteristic feature of wind is that it blows from the high-pressure region to the low-pressure region. There are seven fixed pressure belts found on the earth’s surface.
• These high-pressure and low-pressure belts lie and alternate with each other from the equator to the poles.
• As these pressure belts are fixed, certain fixed winds blow between the two adjacent high-pressure and low-pressure belts. These winds are called planetary winds.
• Planetary winds such as Trades, Westerlies, and Polar winds blow from sub-tropical high-pressure belts to equatorial and polar low-pressure belts over the earth’s surface throughout the year in fixed directions.

Question 37.  Why do the westerly winds blow with more speed in the southern hemisphere than in the northern hemisphere?
Answer:

The westerly winds blow between 35°and 60° latitudes in both the hemispheres.

• The presence of huge landmasses in the northern hemisphere reduces the speed of the winds blowing over them due to friction.
• But in the southern hemisphere, there are more water bodies or oceans than land.
• Hence, the degree of friction is very less, and winds can blow uninterruptedly with great speed over oceans.
• The speed of westerlies in the southern hemisphere is so great that they make roaring, screeching, and shrieking noises as they blow. 

Question 38. Discuss the role of the trade winds in the creation of deserts.
Answer:

The role of the trade winds in the creation of deserts

• The trade winds blow from the subtropical regions to the equatorial regions, i.e, from higher latitudes towards lower latitudes.
• As they blow from comparatively cooler regions to warmer regions, the wind gets warmer.
• The moisture-holding capacity of the wind increases and hence chances of rainfall is reduced.
• Thus, dry weather persists in the regions over which trade winds blow. The hot deserts of Sahara, Thar, Kalahari, Atacama, etc. lie in the path of trade winds.

Question 39. What are local winds? Give examples.
Answer:

Local winds

The winds that blow due to the influence of local geographical features and environmental conditions are called local winds.

Some of the local winds are-

Loo: This is a hot dry wind that blows over north-western India during the daytime.
Foehn: This is a warm dry wind that blows over the northern slopes of the Alps mountains in Europe through the Rhine river valley.

Question 40. What is loo’? When does this wind blow? Where in India is Loo found to blow?
Answer:

Loo

‘Loo’ is a strong, dusty, hot, dry wind. It blows during the summer season (very strong in April-May) in India.

Area: The Loo blows over the Indo-Gangetic Plain region of North India. Rajasthan, Uttar Pradesh, Delhi, and Madhya Pradesh mainly come under its influence.

Question 41. Explain the causes of winds.
Answer:

Causes of winds

• Winds blow from high-pressure regions to low-pressure regions. If the temperature of a place increases, the air becomes warm and tends to rise as it becomes light.
• Thus, a low pressure is created. Cooler winds from adjacent areas rush towards this low-pressure region to fill up the gap. Thus, the main cause of winds is a difference in air pressure.

Question 42. What do you mean by air pressure?
Answer:

Air pressure

Air pressure is an important element of weather and climate. Air has mass, and like any other material having mass, it is attracted by gravity.

Thus, the weight that a unit volume of air exerts on the earth’s surface is known as air pressure. Under normal conditions, air pressure is 1 kg per square centimeter.

Question 43. What are isobars?
Answer:

Isobars

• Isobars are imaginary lines drawn on weather maps joining places having the same pressure conditions.
• The air pressure decreases by 34 millibars with a 300 m rise in height above sea level.
• Thus, before drawing the isobars, the pressure conditions of the places concerned must be converted to pressure conditions at sea level height.

Question 44. Why do mountaineers use oxygen cylinders in high altitudes in the Himalayan region?
Answer:

• Air pressure remains high near the earth’s surface or the mean sea level and goes on the same decreasing with an increase in altitude as the air becomes thinner with the rise in altitude.
• The density of air decreases with decreasing air pressure. The amount of oxygen left in the upper air is not sufficient for normal breathing.
• Hence, mountaineers use oxygen cylinders when they go to higher altitudes or for climbing peaks

Question 45. Why have hot deserts been formed in the path of the trade winds?
Answer: The trade winds blow from the subtropical regions to the equatorial regions, i.e, from higher latitudes towards lower latitudes. As they blow from comparatively cooler regions to warmer regions, the wind gets warmer.

The wind’s moisture-holding capacity increases, reducing the chances of rainfall. Thus, dry weather persists in the regions over which trade winds blow. The hot deserts of the Sahara, Thar, Kalahari, Atacama, etc. lie in the path of trade winds.

Question 46. Why don’t we feel the pressure exerted by the earth’s atmosphere on us?
Answer:

• Air pressure is 76 cm of mercury column which is about 10,360 kg per square meter.
• The atmospheric pressure of the air around us is almost the same or similar to the pressure exerted by blood in our bodies.
• Thus, there is a balance between atmospheric pressure and body pressure.
• Hence, we do not feel the atmospheric pressure exerted by the column of air in the atmosphere around us.

Question 47. Why does air pressure decrease with an increase in altitude?
Answer:

The air pressure decreases with an increase in altitude because of the following reasons—

1. The density of air decreases with an increase in altitude. Air becomes thin, and light, and hence pressure decrease.
2. The number of air molecules or gaseous molecules present in higher altitudes is lesser than that present at lower altitudes.
3. Air pressure decreases by 1 cm of mercury column with every 110 cm rise in altitude. If the air pressure at sea level is considered 100%, it becomes about 1% at an altitude of 18 km.

Question 48. What is the unit for measuring air W pressure?
Answer:

The unit of ‘millibar’ is used to measure air pressure.

1 millibar is equivalent to 1000 dyne per sq. cm. Dyne is the unit of measuring force.
1 dyne is almost equal to 1 kg. Air pressure is measured with the help of a barometer. The mercury column in the barometer indicates the pressure conditions of the surrounding area.

Question 49. What is a jet stream?
Answer:

Jet stream

The thin stream of air blowing through the I upper atmosphere from the west to the east
at a very high speed (110-500 km/hr) is known as the jet stream. The tropical and sub-tropical jet streams influence the climate of India.

Question 50. What are trade winds?
Answer:

Trade winds

The planetary winds that blow from the subtropical high-pressure zones in the northern and southern hemispheres towards the equatorial low-pressure zone in a particular direction throughout the year, are called trade winds.

They are basically easterly winds, i.e., they blow from the northeast to the southwest in the northern hemisphere and from the southeast to the northwest in the southern hemisphere. In the early days, these winds helped in trading across the oceans by sailing ships. Hence, they are called the trade winds.

Question 51. What are anti-trade winds
Answer:

Anti-trade winds

The planetary winds that blow in the opposite direction of trade winds are called anti-trade winds. In both the northern and southern hemispheres, the winds blow towards the sub-polar low-pressure zone near the Arctic and Antarctic circles from the high-pressure zone near the tropics.

The direction of the wind in the northern hemisphere is from southwest to northeast, and that in the southern hemisphere is from northwest to southeast. Thus, these winds are also known as westerly winds

Question 52. Why are the westerlies more speedy in the southern hemisphere?
Answer:

• The amount of landmass is greater in the northern hemisphere than in the southern hemisphere. Thus wind gets obstructed in the northern hemisphere by the land and slows down due to friction.
• On the other hand, winds blow unhindered in the southern hemisphere over the oceans. Thus, wind speed is greater in the southern hemisphere than in the northern hemisphere.

Question 53. What are roaring forties?
Answer:

Roaring forties

In the southern hemisphere, the presence of landmarks is very less beyond the 40JS latitude. Thus, the westerly winds blow with extreme speed over the oceans due to very less friction with the water. These winds make much noise while blowing. Hence, the latitude adjacent to the 40°S latitude is referred to as the roaring forties.

Question 54. What are planetary winds?
Answer:

Planetary winds

The winds that blow over the earth throughout the year from a fixed direction without much fluctuation, are called planetary winds. They can be classified into three types-

1. Trade winds,
2. Westerlies and
3. Polar winds.
4. The planetary winds develop due to the rotation of the earth and the existence of the pressure belts around the earth.

Question 55. What do you mean by monsoon winds?
Answer:

Monsoon winds

Monsoon winds are periodic winds generated in certain places due to differences in temperature and pressure conditions on land and water in different seasons of the year. Monsoon winds blow from opposite directions in different seasons of the year.

If the southwest monsoon blows over the Indian subcontinent from the southwest direction during summer. It blows from the reverse direction as the northeast monsoon wind during winter.

Question 56. What is a cyclone?
Answer:

Cyclone

• A cyclone is a sudden wind developed due to a sudden difference in pressure conditions in a region.
• If a low-pressure cell is created at any point due to excessive heating, winds from the adjacent high-pressure regions gush toward the low-pressure cell in circular motions with great speed.
• Cyclones can be highly devastating and may last from a few hours to a few days. They may cause heavy rainfall if they are generated near coastal areas.

Cyclones can be classified into two types—

1. Tropical cyclones and
2. Temperate cyclones.

Question 57. What do you mean by the eye of a cyclone?
Answer:

Eye of a cyclone

• The low-pressure cell at the center of a tropical cyclone is known as the eye of the cyclone. It can extend from 20-40 km in diameter.
• The weather conditions in the eye remain calm and cloudless even though severe storms and rainfall may occur in other parts of the cyclone.

Question 58. What is’Chinook7?
Answer:

‘Chinook7

• The ‘Chinook7 is a local wind blowing from the eastern slopes of the Rocky Mountains in North America towards the Prairie region at the foothills of the mountains.
• These are hot and dry winds that cause the snow of the Prairie region to melt. The word ‘Chinook7 means ‘snow eater.
• As this wind melts all the show, it has been so named. The snow melt water moistens the soil of the Prairie region and helps in the growth of vast grasslands.

Question 59. What is ‘Foehn7?
Answer:

Foehn7

‘Foehn7 is a local wind blowing from the Alps mountainous region towards the Rhine valley in Europe.

Effects: The hot and dry wind rises along the slope of the Alps mountains and starts cooling down. The water vapor present in the air condenses and causes rainfall and snowfall.

As the wind crosses the Alps mountains and moves down-slope towards the Rhine valley, it starts expanding. Thus, it becomes warm and dry.

Question 60. What is Sirocco?
Answer:

Sirocco

The hot, dry, dusty wind blowing locally over the Sahara desert is called Sirocco

Effects: The hot dry wind becomes humid as it moves towards the northeast and crosses the Mediterranean sea.
The Sirocco is harmful to the cultivation of olives in Italy and Sicily.

Question 61. What is a loop?
Answer:

Loo

The hot dry local wind blowing in northwestern India is called ‘Loo’. During summer, the land surface in north-western India gets extremely heated.

The air adjacent to this land also gets heated by radiation of this heat. During the afternoon, this heated air blows as very speedy wind parallel to the earth’s surface. The local people call this hot wind ‘Loo’.

Question 62. What is ‘Aandhi’?
Answer:

‘Aandhi’

The Aandhi is a violent, squally dust storm occurring in the summer season in northwestern states of India over Uttar Pradesh, Rajasthan, and Punjab. The wind blows at a very high speed, about 70-100 km per hour.

Question 63. The dust particles blown up by the wind reduce visibility to almost zero and makes
Answer: The surroundings are dark. Hence, it is named ‘Aandhi’ meaning darkness.

Effects: These dust storms may cause very little rainfall. Aandhi helps to reduce the air temperature and the weather feels pleasant after the storms stop blowing.

Question 64. What is a hurricane?
Answer:

Hurricane

The strong tropical cyclone that develops over the Caribbean sea and the islands of the West Indies is called a hurricane. The hurricane may have a diameter of 650 km and blow at an average speed of more than 140 km/hr.

The eye of the hurricane consists of a very deep low-pressure cell.

Question 65. What is a tornado?
Answer:

A violently rotating column of air extending from the base of a thunderstorm to the ground is called a tornado. Tornadoes are often associated with funnel-shaped clouds. In the USA, tornadoes are also known as twisters.

Characteristics:

1. The speed of these storms may reach up to 500 km/hr.
2. The center of the tornado maybe 100-500 m in diameter.
3. A number of tornadoes generated close to each other over a region are considered as the tornado family.

Question 66. What is Mistral wind?
Answer:

Mistral wind

The strong, cold dry north-westerly wind blowing from the Alps mountain region to the Rhone valley in France in Europe, is known as the Mistral wind. The Mistral wind can reach velocities of 130 km per hour.

Question 67. What is Bora wind?
Answer:

Bora wind

The very strong cold wind blowing over northern Italy and the eastern coast of the Adriatic sea in Europe during the winter, is known as Bora. These winds often reach a speed above 120 km/hour and create cloudless skies and cold weather conditions.

Question 68. What do you mean by weather and climate?
Answer:

Weather:

• The condition of temperature, air pressure, humidity, cloudiness, rainfall, snowfall, etc. of a certain place at a certain time is known as weather.
• The weather may persist for a few moments, a few hours, or a few days.

Climate:

• The average weather conditions persisting over an area for at least 35 years is known as the climate.
• In other words, the climate is the average of weather conditions over a long period of time.

Question 69. Why are easterly winds also called Trade winds?
Answer:

• In earlier days, ships used to sail across the oceans in the direction of the easterly winds for trade and commerce between the countries lying in the tropical region.
• As the winds helped in trade by helping the ships to move faster along the direction of the winds, they came to be known as Trade winds.

Question 70. What are anticyclones?
Answer:

Anticyclones

• Anticyclones are the opposite conditions of cyclones. In the Temperate and Frigid zones, over a small area of land, air may suddenly get cold and heavy and start moving downwards.
• This creates a deep high-pressure cell over the area. In such a condition, the winds start gushing out of the high-pressure region towards the adjacent low-pressure regions in circular motions.
• This is known as an anticyclone. Anticyclones rotate in a clockwise direction in the northern hemisphere and an anticlockwise direction in the southern hemisphere.

Question 71. What is the Buys Ballot’s Law?
Answer:

Buys Ballot’s Law

The Buys Ballot’s Law was proposed by the eminent scientist Buys Ballot during the 19th century. According to the law, if one stands with his back facing the wind direction in the northern hemisphere, air pressure felt on the left side is less than the pressure on the right side. The reverse condition is experienced in the southern hemisphere.

Question 72. What are the water column and sand column?
Answer:

• Water column: When a severe storm passes over an ocean, the cyclonic winds attract the ocean water and pull it upwards. Thus, the water rises like a pillar over the ocean. This is known as the water column.
• Sand column: When a cyclone blows over a desert region, it may attract the sand particles from the desert surface and draw them upwards, thus forming a big pillar of sand. This is known as the sand pillar.

Question 73. What is Sea breeze?
Answer:

Sea breeze

• The sea breeze is an example of periodic wind. In coastal regions during the daytime, the land gets heated and causes the air to get heated accordingly.
• This warm air becomes lighter and rises upward, thus creating a partial vacuum over land. The cool winds from the sea rush towards the land to fill up this vacuum.
• This is known as the ‘Sea breeze’. The maximum speed of the sea breeze occurs during the afternoon when the difference in temperature between land and sea is at its highest. [Winds blow from the sea to land].

Question 74. What is a land breeze?
Answer:

Land breeze

• Land breeze is an example of periodic winds in coastal regions. At night, the sea is warmer than the land. Thus, the air over the sea becomes warmer than the land.
• This warm air becomes lighter and rises upwards, creating a vacuum over the sea.
• Cool winds from the land then rush towards the sea to fill up the partial vacuum. This is known as a land breeze. The maximum speed of the land breeze occurs in the early morning [Winds blow from the land to the sea].

Question 75. What are geostrophic winds?
Answer:

Geostrophic winds

The thin streams of wind generated in the upper part of the atmosphere at 6-8 km altitude, parallel to the isobars are called geostrophic winds. Such winds are produced when the pressure gradient force and Coriolis force come into balance and the condition is called geostrophic balance.

Question 76. What do you mean by absolute humidity and relative humidity?
Answer:

Absolute humidity: The total amount of water vapor present in a unit volume of air at a particular temperature is known as absolute humidity. This is expressed in gm/kg.

Relative humidity: The ratio between the absolute humidity to the total amount of humidity that the volume of air can hold at that particular temperature, is known as relative humidity. This is represented in percentage (%).

Relative humidity = Absolute humidity at a particular temperature/Total humidity that the particular temperature 100

Question 77. How is Cyclonic rainfall caused?
Answer:

The rainfall caused by the formation of cyclones is known as cyclonic rainfall. If a low-pressure cell is created over land, winds from the surrounding high-pressure regions gush in circular motions toward the low-pressure cell to fill up the region. If the winds are moisture laden, they cause rainfall.

Processes:

1. In tropical regions, if a low-pressure cell is created, winds from high-pressure regions gush in and start rising upwards with great speed. These winds get cooled as they rise, and the water vapor condenses and causes torrential rainfall.
2.  In temperate regions, the cold winds and hot winds meet with each other along a margin known as the front. The hot winds lying below tend to rise upward while the heavy cold winds tend to move downwards. Thus, the water vapor present in hot winds comes in contact with the cold winds and condenses. This causes rainfall.

Question 78. Why does convectional rainfall occur in the equatorial region?
Answer:

In equatorial regions, the land gets highly heated and heats the air adjacent to it. Excessive evaporation occurs due to heat. The moisture-laden warm air tends to rise upward, where it meets cold air and starts condensing.

As the amount of water vapor is very high in the air, the air gets saturated very fast. During the afternoon, when the heat of the earth’s surface reduces considerably, the air cannot hold back the moisture, and drop it as rainfall. This phenomenon goes and repeats in a cyclical manner due to convection currents of air. Thus, convectional rainfall occurs in the equatorial region.

Question 79. Where is the monsoon climate seen in the world?
Answer:

The region lying between 10° and 25° latitudes in both the northern and southern hemispheres experiences a monsoon climate. The countries where monsoon climate is found are-

1. Asia: India, Bangladesh, Laos, Myanmar, Pakistan, Cambodia, Thailand, Vietnam, etc.
2. Africa: Liberia, Western Madagascar.
3. Australia: Northern part of Australia.
4. North America: South-eastern part of USA.

Question 80. List the characteristic features of monsoon climate.
Answer:

The characteristic features of monsoon climate are —

1. Four prominent seasons are experienced in this climate namely, summer, rainy autumn, and winter.
2. The temperature remains around 27-32°C in
3. The annual range of temperature is seasonal

Question 81. List the characteristics and features of a hot desert climate
Answer:

The characteristic features of a hot desert climate are—

1. The temperature rises as high as 40- 45°C in summer.
2. Winter temperatures occur between 15 and 21°C.
3. The diurnal range of temperature is very high.
4. Rainfall is very scanty in desert regions. Annual rainfall is about 10-15 cm.
5. In certain deserts, rainfall occurs at an interval of 2-4 years.

Question 82. Mention the areas of the world experiencing Mediterranean climate.
Answer: Mediterranean climate is found between 30 and 40° latitudes in both the northern and southern hemispheres.

The regions experiencing such climate are-

1. Europe: Portugal, Spain, Italy, Greece.
2. Asia: Western Turkey, Lebanon, Israel, Syria.
3. Africa: Egypt, Libya, Morocco, northern Algeria, Cape Town of southern Africa.
4. North America: Southern California.
5. South America: Chile.
6. Oceania: Southern and south-western coast of Australia.

Question 83. What are the characteristics of the Mediterranean climate?
Answer:

The characteristics of the Mediterranean climate are—

1. The temperature remains moderate throughout the year. The average temperature is around 20-27°C.
2. During winter temperature may drop to 5-10°C.
3. The average annual range of temperature is 15-17°C.
4. The summers are dry and the sky remains clear.
5. Rainfall occurs during winters due to the influence of the moist westerly winds causing cyclones. The average annual rainfall is 37-65 cm.

Question 84. Discuss the role of humidity in the air.
Answer:

The humidity influences the weather and climate of a region to a great extent.

The role of humidity in the air is—

1. Water vapor is the cause of any kind of condensation and precipitation.
2. Water vapor controls the temperature in the atmosphere.
3. The rate of evaporation remains very less if the presence of humidity in the air is high. If the presence of humidity is less, the rate of evaporation becomes high

Question 85.  Why is rainfall not produced by all the clouds?
Answer:

A cloud is created by condensation of water vapor on dust particles, sea salt nude, etc. in the upper atmosphere, and the accumulation of tiny droplets of water thus formed.

All clouds do not cause rainfall because of the following reasons—

1. The average diameter of water droplets forming the clouds is about 0.01 min. Unless they are at least 0.05 mm, they cannot fall down as rain. Even while falling down as rain, if the water droplets encounter a warm layer, they again evaporate back.
2. The tiny droplets of water must accumulate and join with each other to grow in size and fall as rain.
3. Condensation does not occur unless the relative humidity reaches 100%, hence no rainfall occurs

Question 86. Write down the characteristics of convectional rainfall.
Answer:

The characteristics of convectional rainfall are enough heat to cause evaporation, the air remains filled with a huge quantity of water-

1. Location: This type of rainfall occurs between 5 and 10° latitudes on either side of the equator

2. Time: This rainfall occurs the over the world. The equatorial region receives almost vertical rays of the sun, while the poles receive inclined rays. Thus, heat is maximum at the equator and goes on decreasing toward the poles. This leads to the year in the equatorial region, and at the beginning of summer in the temperate region.

3. Amount: On average, about 200-300 cm of rainfall occurs in the equatorial region

4. Name: Convectional rainfall occurs during the afternoon in the equatorial region every day. Hence, it is called the 4 o’clock rain.

5. Cloud: The rainfall is caused by cumulonimbus clouds.

6. Thunder: This type of rainfall causes thunder and lightning. E.g.—Java island has a record of 322 days of lightning in a particular year.

7. Nature of rainfall: Heavy downpour occurs for a short duration. After the rainfall, the sky becomes clear and bright.

Question 87. Identify the climate and the hemisphere of the region from the given temperature-rainfall diagram

Answer: The temperature-rainfall diagram shows—

1. The temperature curve is not very high.
2. The range of temperature is low.
3. The temperature graph remains the same throughout the year.
4. Temperature lies between 26 and 28°C.
5. Rainfall occurs throughout the year.

Conclusion: The diagram represents the equatorial climate. The temperature remains the same almost throughout the year. The little increase in temperature during the months of May and June shows that this is a diagram of the northern hemisphere.

Question 88. Identify the climate from the given temperature-rainfall diagram. Which hemisphere is depicted here?

Answer:

The temperature-rainfall diagram shows that:

1. May is the hottest month and January-February is the coolest month.
2. Most of the rainfall occurs during June, July, and August. A little rainfall occurs in winter.

Conclusion: The diagram depicts the tropical monsoon climate. May-June is very hot compared to other months. This depicts that this is a diagram of the northern hemisphere.

Question 89. Find out the climate depicted in the temperature-rainfall diagram. Detect the hemisphere being shown

Answer: The temperature-rainfall diagram shows that—

1. The temperature remains below the freezing point for the entire year except during June and September.
2. The temperature in January is -23°C.
3. The convex shape of the curve depicts that this is a diagram of the northern hemisphere.
4. Rainfall is very low, snowfall is profuse.

Conclusion: Chilling cold temperature, little rainfall, and the convex temperature graph indicate that this is a diagram of the Tundra region of the northern hemisphere

Question 90. What problems are caused by daily life?
Answer:

The problems caused by fog in our daily life are:

1. Fog reduces visibility. Thus, it becomes difficult to run trains, cars, and buses, especially on highways.
2. In urban and industrial regions, fog combines with the smoke of vehicles and chimneys, creating smog.
3. Fog is harmful to crops.
4. Fog influences the local climate of a place

Question 91. Identify the climate and hemisphere of the place from the given temperature-rainfall diagram.

Answer:

The given temperature-rainfall diagram shows that:

1. The temperature curve is concave. Thus, it definitely depicts a place in the southern hemisphere.
2. June, July, and August receive the maximum amount of rainfall.
3. The temperatures are found in July-August and are called the rain shadow area.

Question 92.  Identify the climate and hemisphere of the place from the given temperature-rainfall diagram.

Answer:

The temperature-rainfall diagram shows that:

1. The temperature curve is convex and the highest temperature recorded in July-August is 33°C.
2. Average annual rainfall is lower than 10 cm.

Conclusion: The diagram depicts locations in the northern hemisphere. Very hot summers and very less rainfall show that the place enjoys a hot desert climate.

Question 93. What do you mean by saturated air?
Answer:

Saturated air

• Air can hold different amounts of water vapor at different temperatures. At a particular temperature, if the air holds the maximum possible amount of water vapor, the condition of the air is said to be saturated.
• If the temperature of the air decreases, the moisture-holding capacity of the air also decreases and the extra water falls onto the earth’s surface as precipitation.
• But if the temperature of the air increases, the moisture-holding capacity of the air also increases and the air will not be saturated with the amount of water vapor it was holding previously.

Question 94. What is dew point
Answer:

Dew point

The temperature at which the air becomes saturated and the water vapor starts condensing is known as the dew point. At the dew point temperature, the relative humidity of air remains 100%. The water vapor starts changing into small droplets of water by condensation.

Question 95. What is the importance of relative humidity?
Answer:

The importance of relative humidity is—

1. Relative humidity gives an idea of the occurrence of rainfall, snowfall, dew, etc.
2. The rate of radiation of heat from the earth’s surface can be calculated from relative humidity.

Question 96. What is precipitation?
Answer:

Precipitation

• The water vapor present in the air on rising upward gets cooled gradually and starts condensing into very small crystals of ice in the upper atmosphere. These crystals of ice and tiny droplets of super-chilled water accumulate together to form clouds.
• As more and more ice crystals and water droplets accumulate, the cloud grows bigger in size and becomes heavy. Thus, they are pulled downwards towards the surface of the earth by gravitational force.
• This is known as precipitation. Precipitation may occur in the form of rain, sleet, drizzle, snow, hailstorm, etc

Question 97. What is humidity?
Answer:

Humidity

• The measure of water vapor contained in the air is known as humidity. Air can hold different amounts of humidity at different temperatures.
• If the air holds the maximum amount of water vapor possible at a particular temperature, it is said to be saturated. If the air can hold some more water vapor at that particular temperature, it is said to be unsaturated.

Question 98. What is absolute humidity?
Answer:

Absolute humidity

• The total amount of water vapor actually contained in a particular volume of air at a particular temperature is known as absolute humidity. It is expressed in gm/kg.
• If the temperature of the air changes, but the amount of water vapor in the air is kept constant, the relative humidity of the air will change, but the absolute humidity will remain the same.

Question 99. What is unsaturated air?
Answer:

Unsaturated air

The moisture-holding capacity of air depends upon its temperature. If at a particular temperature, the air contains less amount of water vapor than it can actually hold at that temperature, it is said to be unsaturated. An unsaturated air may become saturated if the temperature of the air is lowered. Similarly, saturated air may become unsaturated if the temperature is increased.

Question 100. What is snowfall?
Answer:

Snowfall

• Water vapor condenses and forms tiny ice crystals in the upper atmosphere as they rise upward along with air. These ice crystals accumulate together and form clouds.
• When they become much bigger and heavier, they start falling towards the earth’s surface as precipitation. If the air temperature is higher at lower altitudes the ice crystals melt and fall downwards as rain.
• But in mountainous regions and high altitudes, where the temperature is lower than the freezing point, the ice crystals need not melt and come down as snowfall.

Question 101. What is a hail storm?
Answer:

Hail storm

• Water vapor in the air rises upward along with air currents, cools down, and condenses, forming tiny crystals of ice. These crystals accumulate together and form clouds of ice.
• When the clouds thus formed become quite heavy, they start moving downward as precipitation.
• The warm air below forces some of the ice crystals to melt and fall as rain. But if the temperature suddenly drops after the occurrence of rain for some time, the ice crystals may come downward in solid form along with rainfall. This combination of ice crystals and rainfall is known as a hailstorm.

Question 102. How many types of rainfall are there? Name them.
Answer: Rainfall occurs due to condensation of water vapor present in the air. Rainfall can be classified into three types—

1. Convectional rainfall,
2. Orographic rainfall and
3. Cyclonic rainfall.

Question 103. What are warm and cold fronts?
Answer:

Warm and cold fronts

The sloping boundary that separates two contrasting air masses is known as the front.

1. A warm front is the gently sloping frontal surface along which the light warm air becomes active and gently rises over the cold dense air.
2. A cold front is the sloping frontal surface along which the dense cold air becomes active, but, being dense this air remains on the ground and forcibly uplifts the light warm air.

Question 104. What do you mean by occlusion?
Answer:

Occlusion

Occlusion is a stage in the life of a temperate cyclone. Since its genesis, after which the cyclone dies out. The cold air displaces the warm air from the ground and the warm air glides over the cold air.

The cold front moves faster than the warm front, ultimately the former overtaking the latter. The warm air is completely lifted up, the front thus formed is an occluded front and the cyclone dissipates thereafter.

Question 105. What is the relation between humidity and temperature?
Answer:

Relation between humidity and temperature

• Relative humidity is inversely related to temperature. In a particular volume of air, if the total amount of water vapor is kept constant, the relative humidity increases when the temperature of the air decreases.
• The relative humidity decreases if the temperature of the air increases.
• This is because the moisture-holding capacity of air is dependent on the temperature of the air.

Question 106. Why are rain shadow areas created on the leeward slope of mountains?
Answer:

• Moisture-laden winds cause rainfall on the windward slope of mountains.
• After showering rainfall, the winds become lighter and can easily cross the mountains, reaching the leeward side.
• On the leeward side, the winds have very little moisture, which fails to cause much rainfall.
• Moreover, these winds blow downward along the slopes of the mountain. As they reach lower altitudes they became warmer and moisture-holding capacity increases. Thus, they fail to cause rainfall with the little amount of water vapor present in the air. This turns the leeward slopes of the mountains into rain shadow areas.

Question 107. What is frost?
Answer:

Frost

• As the air temperature reaches the dew point, the atmospheric water vapor starts changing into tiny droplets of water called dew drops.
• If the air temperature falls below the dew point and reaches the freezing point, the dew drops tend to freeze into tiny crystals of ice. This is known as frost.

Question 108. On which factors does evaporation depend?
Answer:

Evaporation depends on the following factors—

1. Nature of landforms,
2. Height of water bodies,
3. Relative humidity of the air,
4. Wind speed.

The rate of evaporation is not the same all over the earth. It is highest near the tropical desert regions.

Question 109. Name the instrument by which humidity can be measured.
Answer:

1. Humidity is measured with the help of a hygrometer or rain gauge.
2. The relative humidity is measured by the Six’s maximum and minimum thermometer.
3. Recently, numerous kinds of hygrometers have been invented, that measure humidity.

The common types of such hygrometers are-

1. Dew point hygrometer,
2. Hair tension hygrometer,
3. Resistive hygrometer, etc.

Question 110. Why does fog occur in urban areas and industrial zones?
Answer:

• The sky in the urban centers and industrial zones remain filled with suspended particles of carbon, dust, and other aerosols.
• During the night, when these particles get cooled, the water vapor present in the atmosphere condenses on them and forms many tiny water droplets that remain suspended in the air.
• This is known as fog. Fog reduces visibility considerably.

Example:  The iron and steel centers of Durgapur and Jamshedpur.

Question 111. List the significance of humidity in the air.
Answer:

The importance of humidity in the air is as follows—

1. Humidity helps in conducting the water cycle.
2. Condensation occurs due to the presence of water vapor.
3. The heat radiated by the earth is arrested by the water vapor.
4. Too much relative humidity makes the air very moist and feels very uncomfortable. Lack of humidity (in winter) makes the air very dry.

Question 112. What is the lower course or delta course of a river?
Answer:

Lower course

• The course where the river flows through a plain land till it reaches the mouth of the river in a sea, lake, or any other depression, is called the lower course of the river.
• This course spreads through the delta region. E.g.-The portion of the river Ganga, lying between south of Rajmahal hills to the mouth in the Bay of Bengal is known as the lower course of the river.

Long Question And Answers

Question 19. What is the water cycle? How is water transported through the water cycle?
Answer:

Water cycle

The circulation of water from the earth to the atmosphere and back occurring in a cyclical manner is known as the water cycle. Water escapes from the earth s surface, oceans, and other water bodies and underground into the atmosphere in the form of water vapor.

Later, this water comes back to the earth’s surface in solid or liquid form. Thus, the balance of water present in the atmosphere, lithosphere, and hydrosphere is maintained by the water cycle.

 

Transportation of water:

1. Evaporation: The sea is the main source of free water or open water. Other sources of water are rivers, lakes, ponds, canals, etc. Water evaporates from these water bodies and also from the underground and from plants and reaches the atmosphere as water vapor.
2. Condensation: The water vapor present in the atmosphere condenses on the dust and salt particles present in the atmosphere and changes back to water droplets or ice crystals. These droplets accumulate together and fall as rain or snow when the temperature permits.
3. Precipitation: The tiny water droplets or ice crystals formed in condensation, accumulate together, become heavy, and tend to fall downward. This is known as precipitation. It may occur in the form of rain, snow, hail, drizzle, etc.

Thus, the water cycle comprises evaporation, condensation, and precipitation, without which the circulation of water would not have been possible.

Question 7. Where is the equatorial climate formed in the world?
Answer:

Equatorial climate is formed within 5°-10° latitude in both northern and southern hemispheres.

The regions where the equatorial climate is found are as follows—

1. Asia: India, Bangladesh, Laos, Myanmar, Pakistan, Cambodia, Thailand, Vietnam, etc.
2. Africa: Liberia, Western Madagascar.
3. Australia: Northern part of Australia.
4. North America: South-eastern part of USA.

 

Question 8 List the characteristic features of equatorial climates.
Answer:

The characteristic features of the equatorial climate are—

1. The temperature remains high throughout the year. The diurnal range of temperature is very small. There is no change of seasons.
2. The average annual temperature is about 27°C, and the annual range of temperature is about 2°-3°C.
3. The sky remains covered with clouds during the afternoon due to the excessive rate of evaporation.
4. Rainfall occurs every day during the afternoon. This is also known as 4 o’clock rain.
5. Cyclones or heavy storms do not occur here due to the presence of the calm region nearby experienced in this climate namely, summer, rainy season, autumn, and winter.

Question 9 Where hot desert climate found in the world?
Answer: Hot desert climate is found between 15 and 35° latitudes in both the northern and southern hemispheres.

The regions where the hot desert climate is found are—

1. Africa: Sahara, Kalahari and Namib deserts
2. Asia: Saudi Arabia, Lebanon, Iran, the Thar desert of India, and Pakistan.
3. Oceania: Australian deserts.
4. North America: Arizona desert.
5. South America: Atacama desert.

Question 33. What are pressure cells?
Answer:

Pressure cells

The pressure belts sometimes break into small portions and lie over small regions in the shape of cells. This occurs due to differential.

This occurs due to differential heating of water and landmass and hence the development of high-pressure and low-pressure conditions on land and water accordingly.

The location of the continents and oceans and their shapes lead to the formation of a number of pressure cells in the northern hemisphere compared to the south.

Question 36. What do you mean by pressure gradient?
Answer:

Pressure gradient

The isobars are imaginary lines to join places having the same pressure conditions. The pressure gradient refers to the difference in pressure conditions over a unit distance in an area. It is measured as the force per unit area in a region.

pressure gradient = Vertical Interval (VI)/Horizontal Equivalent (HE)

Where, VI = Difference in pressure between two places HE = Actual horizontal distance between the two places
In a weather map,

1. The pressure gradient is high or steep if the Pressure gradient = isobars lie very close to each other over a period of time
2. The pressure gradient is gentle when the isobars lie far away from each other.
3. The pressure gradient will become steeper with increasing differences in air pressure between the two places.
4. Winds blow with greater speed if the pressure gradient is steep, while winds blow with less speed if the pressure gradient is normal or gentle.

Question 26. What are mountain breeze and valley breeze?
Answer:

Mountain breeze: In the mountainous regions during the night, the air cools down and becomes heavy due to radiation of heat, and slips downwards along the slope.

This causes the warm air to stay above the cold air. These breezes or winds are known as katabatic winds.

 

Valley breeze:

In mountainous regions during the daytime, air starts getting heated, becomes lighter, and tends to rise along the slopes of the mountain valleys and yield precipitation on reaching greater heights. These are known as anabatic winds or valley breezes or winds. Valley breezes cause the formation of clouds in the upper parts of the mountains.

Chapter 2 Atmosphere Topic 4 Humidity And Precipitation

Question 1 How does rainfall occur?
Answer:

Rainfall occurs through the following processes

Air Contains some account of water vapor, Which makes the air light and it tends to rise.

• As the moist air rises upward, pressure decreases, and the air starts cooling down.
• Gradually, the air in the upper atmosphere starts getting saturated, as the moisture-holding capacity of the air decreases with an increase in altitude. When the temperature of the saturated air falls below the freezing point, the extra water vapor starts condensing on the dust particles, carbon, and salt particles floating in the air, forming tiny droplets of water and ice crystals.
• The water droplets thus formed collide with each other and adhere to form bigger droplets.
• These bigger droplets become heavy and cannot float in the air anymore.
• Thus, they fall as rainfall. If the temperature in the lower layers is quite low, snowfall may occur instead of rainfall.

Question 2 Describe the different types of rainfall. OR’ Discuss the difference between rain, a and give examples
Answer:

Rainfall is classified into three types according to their mode of origin:

 

 

Rainfall	concept	Method	Example
Correctional rainfall	The moisture-laden air rises upward due to excessive heating of the earth’s surface, cools down, and causes rainfall.	In hot regions, where there are enough water bodies, the water evaporates in huge amounts due to excessive heat. This rises upward along with the air, gets cooled, and condenses on the dust and salt particles, forming clouds. In the afternoon, when the surface temperature falls, the air gets saturated and cannot hold back the water droplets in the clouds. Thus, they come down as rainfall. This process goes on in a cyclical form, and so is called convectional rainfall.	Convectional rainfall occurs In the equatorial region throughout the year in the afternoon. It is also known as the 4 o’clock rain.
Orographic	The moisture-laden air collides with the hill slopes, it rises and gets cooled and causes rainfall.	If the moisture-laden air is obstructed by high landforms in its path, it rises upward. Here, it gets cooled and condenses to cause enough rainfall. After shedding water, the air becomes lighter and rises higher. As it crosses the mountains and blows over the leeward side, due to insufficient moisture very little rainfall occurs. Thus, this region becomes a rain shadow area. As the air slips down the slope of the leeward side, its temperature and moisture-holding capacity increase. Thus, the chances of rainfall decrease even more. enough rainfall. After shedding water, the air becomes lighter and rises higher. As it crosses the mountains and blows over the leeward side, due to insufficient moisture very little rainfall occurs. Thus, this region becomes a rain shadow area. As the air slips down the slope of the leeward side, its temperature and moisture-holding capacity increase. Thus, the chances of rainfall decrease even more.	The western slope of the Western Ghats, foothills of the Himalayas, the Mawsynram, and Cherrapunjl in Meghalaya all receive rainfall due to the southwest monsoons.

 

Convention Rainfall:

Orographic Rainfall:

Cyclonic Rainfall:

 

Question 3 How is rainfall caused by temperate cyclones?
Answer: In temperate regions, two air masses of opposite characteristics meet each other along a front. The cold and dry air coming from the northeastern side meets the warm moist air coming from the southwestern side along a front.

The warm air enters the cold air from below and the cold air enters the warm from the top. The place where the warm air meets the cold air is known as the warm front. The place where the cold air hits the warm air from the back is known as the cold front.

Rainfall at the warm front: The warm air rises upward through the cold air. In this process, the water vapor present in the warm air comes in contact with the cold air and condenses. This causes rainfall.

 

Rainfall at the cold front: The cold air pushes the warm air upward from the back. Thus, the warm air rises up and cools down and the water vapor present in the warm air starts condensing. This causes heavy rainfall with thunder and lightning.

Regions: Rainfall from temperate cyclones occur in many places in Europe during the winter season.

Question 4 How does rainfall occur from tropical cyclones?
Answer: Tropical cyclones occur between 5-20°N and S latitudes during summers. Excessive heating of the region causes the development of low-pressure cells on the land.

Cool and heavy air from the adjacent areas gushes with great speed toward the low-pressure cell in circular motions. This air gradually rises upward in a circular motion and starts becoming cooler.

The water vapor present in the air condenses. The center or eye of the cyclone remains calm, but winds from the surrounding areas rush with such speed that they cause severe storms along with heavy rainfall.

Example: Cyclones originate in the Bay of Bengal when the eastern coastal regions of India get heated in the summer season and develop low-pressure cells. This type of cyclone forms when the warm and moist southwest monsoon winds meet with the hot dry winds on land. Such a weak cyclone may cause rainfall for a few days continuously.

Question 5 Classify precipitation.
Answer:

Precipitation:

The warm and moist air tends to rise upward and the water vapor condenses to form tiny droplets of water or ice crystals.

These crystals and droplets come close and adhere to each other, thus growing in size. When they grow quite big, they cannot float in the air, and thus fall on the earth’s surface due to gravitational force.

This is known as precipitation. Precipitation may occur in two forms—

1. Liquid and
2. Solid.

1. Liquid:

• The tiny droplets of water formed due to condensation of water vapor adhere to each other and form clouds.
  When the water droplets grow bigger in size, they come down due to gravity.
• This precipitation in the liquid form is known as rainfall. Rainfall can be of three types— Convectional, Orographic, and Cyclonic.

2. Solid:

1. Snowfall: In higher latitudes or cold regions, the moisture in the air condenses in the upper atmosphere and forms ice crystals. These ice crystals come down as snowfall when they grow bigger in size.
2. Hailstorm: The upward-moving stormy air drives the moisture-laden air to great heights in the atmosphere, where they cool down and condenses to form ice crystals.

These ice crystals become heavy and tend to fall downward. They are once again driven upward by the stormy winds, where they collect more water droplets, freeze and become bigger and heavier.

These large crystals of ice then fall on the earth’s surface along with rainfall as hailstorms. The hailstones that fall with hailstorms have a diameter of 5 to 50 mm.

3. Sleet:

• In cool temperate regions, the rain drops cool down while falling through the cooler layers of the atmosphere, and tend to freeze.
• Thus, precipitation occurs in the form of very small granules called sleet, which have a diameter of less than 5 mm.

Question 6 Discuss the major characteristic ‘and features of Tropical Monsoon climatic regions.
Answer: The tropical monsoon climate extends from 10°-25° latitudes in both hemispheres. In India and Pakistan, the influence of this climatic region extends up to 30°N latitude in the north.

Climatic characteristics:

The major characteristics of the tropical monsoon climatic region are as follows—

1. Wet summers and dry winters:

• In monsoon climatic regions during the summer season, the wet monsoon winds while blowing over the ocean pick up moisture and cause rainfall. But during the winter season
• The cold dry winds blow from the land and do not cause rainfall. Hence, the weather remains dry.

2. Two oppositely blowing winds during summer and winter:

In the monsoon climatic regions, during summer, winds blow from the south while during winter winds blow from the north.

For example:

• In the Indian subcontinent during summer, wet southwest monsoon winds and in winter the dry northeast monsoon winds blow. This reversal of wind system is a typical feature of monsoon climate.
• It can be mentioned here that the word monsoon is derived from the Arabic word ‘Muslim’, meaning season.

3. Moderate temperature:

• Monsoon climatic regions experience 30-32°C temperature in summer and 19-22°C temperature in winter.
• In summer the wet monsoon winds bring rainfall and give relief from sweltering heat conditions.

4. Moderate rainfall:

• In monsoon regions average annual rainfall varies from 75-100 cm.
• However, topography and distance from the sea have a profound influence on the amount of rainfall.

For example:

Mountainous and coastal areas receive very high amounts of rainfall, nearly 150-200 cm.

• In India, Mawsynram lying on the southern slope of the Khasi hills in Meghalaya receive about 1187 cm of rainfall annually.
• But, Shillong lying on the leeward side of the Khasi hills receives only 250 cm of rainfall annually.

Again, Allahabad located far away from the coast receives about 100 cm of rainfall annually.

5. Change of seasons:

The change of seasons is one of the important characteristics of monsoon climate. The onset and retreat of two opposite monsoon winds cause a change of seasons.

For example in the northern hemisphere:

• The cold, dry season lasting from December to February is called winter,
• The hot, dry season from March to May is known as summer,
• The hot, wet season from June to September is called the season of south-west monsoon or rainy season,
• October and November is the season of retreating southwest monsoon or autumn. In the southern hemisphere, the opposite seasons occur during the same period.

Question 25. What are the differences between the land breeze and the sea breeze?
Answer:

The differences between the land breeze and sea breeze are:

Question 26. What are the differences between cyclone and anticyclone? OR, Mention four differences between cyclones and anticyclones.
Answer:

The differences between cyclone and anticyclone

Question 3. How are clouds formed?
Answer:

The water vapor present in warm air rises upward along with the air currents. As it gains altitude, it starts becoming cooler. The moisture-holding capacity of the air decreases with a fall in temperature.

Thus, the air gets saturated at the dew point. The water vapor starts condensing on the dust particles, sea salt nuclei, and tiny ice crystals present in the air and forms very tiny droplets of water or ice. These droplets accumulate together to form clouds. When the clouds become very heavy, they cannot hold the water anymore, and drop them as precipitation.

Question 16 Why does temperature decrease with an increase in altitude in the Troposphere?
Answer:

Temperature decreases with the increase of altitude in the Troposphere at the rate of 6.4° C with every 1000 m altitude. This is known as a normal lapse of temperature.

This happens because of the following reasons—

1. Less radiation received: The atmosphere does not get heated directly. It gets heated up by the radiation received from the surface of the earth. Thus, the lower part of the atmosphere coming in direct contact with the surface of the earth gets more heat than the portion lying above.

2. Less dense air: The layers of air are denser near the earth’s surface and become lighter with increasing altitude. Hence, the upper layers receive less heat.

3. Less heat absorbing capacity: The lower layer of the atmosphere contains more water vapor, dust particles, and sea salt nuclei than the layers above and hence heat retentive and heat absorbing capacity considerably decrease with the increase of altitude.

4. Thin layer of air: The atmosphere gradually thins out with an increase in altitude. For this reason, the air in the upper layers expands quickly and cools rapidly by the release of radiation.

Question 22 Differentiate between weather and climate.
Answer:

The difference between weather and climate are –

• Chapter 1 Exogenetic Processes and Resultant landforms
• Chapter 2 Atmosphere
• Chapter 3 Hydrosphere
• Chapter 4 Waste Management

• Chapter 5 India – Physical Environment
  • Topic 1 Location And Administrative Divisions Of India
  • Topic 2 Physiography Of India
  • Topic 3 Water Resources Of India
  • Topic 4 Climate Of India
  • Topic 5 Soils In India
  • Topic 6 Natural Vegetation Of India
• Chapter 6 India – Economic Environment
• Chapter 7 Satellite Imageries and Topographical Maps

 

 

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India Long Answer Type Questions

Question 1. Discuss the state reorganisation in India from 1947-50. OR, Discuss the political structure of India during the period of 1947-50.
Answer:

The state reorganisation in India from 1947-50

The former country of India was divided into two separate countries—India and Pakistan on 15 August 1947. At that time, independent India possessed 9 Governor ruled states, 4 chief commissioners ruled states and 562 independent native states.

During 1948-49, the native states were included within the state of India under the leadership of Sardar Vallabbhai Patel. Some of them were added to the Governor ruled states while some were converted to princely states. On 26 January 1950, India was declared as a sovereign, socialist, secular, democratic republic.  The Constitution of India was formed.

WBBSE Class 10 Geography Chapter 5 Question Answer

Read and Learn Also WBBSE Solutions for Class 10 Geography and Environment

During this time the states of India were divided into four categories—

Part A (Governor Ruled States]	West Bengal, Assam, Bihar, Orissa, Uttar Pradesh, Madhya Pradesh, Bombay, Madras and Punjab (Total 9 states)
Part B [Former Princely States]	Hyderabad, Madhya Bharat, Mysore, Patiala and East Punjab State Union (PEPSU), Jammu and Kashmir, Rajasthan, Saurashtra and Travancore (Cochin) (Total 8 states)
Part C [Chief Commissioner Ruled States]	Ajmer, Bhopal, Bilaspur, Himachal Pradesh, Kachchh, Coorg, Delhi, Manipur, Tripura and Vindhya Pradesh (a Total of 10 states)
Part D [Central Ruled State]	Andaman and Nicobar Islands

 

Question 2. Discuss the reorganisation of states from 1956 till date.
Answer:

State reorganisation in 1956: The State Reorganisation Commission (SRC) was formed in 1953, under whose recommendations India was reorganised into 14 states and 6 Union Territories on 1 November 1956 The main basis of this reorganisation was language.

States: Pradesh, Kerala, Jammu and Kashmir, West Bengal, Punjab, Bihar, Bombay, Madhya Pradesh, Mysore, Madras and Rajasthan.

Union Territories: Tripura, Andaman and Nicobar Islands, Delhi, Lakshadweep, Manipur and Himachal Pradesh.

State reorganisation during other periods: After the reorganisation of the states in 1956, many

States were further reorganised during different periods. In this course, several states were renamed, e.g.—Madras was renamed as Tamil Nadu, Orissa as Odisha, Mysore as Karnataka, Rajputana as Rajasthan, etc. State reorganisation during other periods is listed below—

Date	State Reorganisation
19 August 1947	The formation of the state of Orissa (now Odisha) was completed,
1 May 1960	The former state of Bombay was divided to form the states of Maharashtra and Gujarat.
1 December 1963	Nagaland was given the status of an independent state.
1 November 1966	The former state of Punjab was divided to form the states of Punjab and Haryana and the Union Territory of Chandigarh.
20 February 1970	The former NEFA (North-East Frontier Agency) was renamed Arunachal Pradesh.
25 January 1971	Himachal Pradesh was converted from a Union Territory to a State.
1 November 1973	The former state of Mysore came to be known as Karnataka.
26 April 1975	Sikkim was included as the 22nd state of India (Formerly it was ruled by Chogyal monarchs).
20 February 1987	The Union Territories of Mi Oram and Arunachal Pradesh were included as the 23rd and 24th states of India
30 May 1987	Goa was included as the 25th state of India.
1993	The capital of India, Delhi, was declared as the ‘National Capital Region.
1 November 2000	The state of Madhya Pradesh was divided to form the 26th state of India, Chhattisgarh.
9 November 2000	The state of Uttar Pradesh was divided to form Uttarakhand, the 27th state of India
15 November 2000	Jharkhand was formed from the former state of Bihar, forming the 28th state of India.
2 June 2014	The 29th state of India, Telangana was formed from the former state of Andhra Pradesh.
31 October 2019	The state of Jammu and Kashmir was divided into two Union Territories, Ladakh and Jammu and Kashmir.
26 January 2020	Dadra and Nagar Haveli and Daman and Diu were formed after the merger of the former Union Territories of Dadra and Nagar Haveli and Daman and Diu.

 

“WBBSE Class 10 Geography Chapter 5 notes”

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India Short Explanatory Answer Type Questions

WBBSE Class 10 Geography Chapter 5 Question Answer

Question 1. Why is India regarded as a ‘miniature world’?
Answer:

India is a peninsular country in south Asia. It is bordered by oceans on three sides and the lofty Himalayan mountains on the northern side. It lies in the northeastern hemisphere and the Tropic of Cancer passes almost through the middle of the country.

Different kinds of physio-graphic features like mountains, plateaus, and plains are present here. Deserts, different types of soils, vegetation, climatic conditions and availability of mineral resources make the country a land of variety. Different species of animals and plants are present here.

Apart from these, different types of languages, cultures, religions, castes and creeds are found here. All these make India a representation of a miniature world.

Question 2. State the location of India according to – ciX latitudinal and longitudinal extent.
Answer:

Latitudinal extent: Latitudinally India lies in the northern hemisphere. The mainland of India extends from 8°4’N in the south (Kerala) to 37°6’N in the north (Jammu and Kashmir).

The southernmost point of India including the islands lies at 6°45’N (Indira Point or Pygmalion point of Great Nicobar Island).

Longitudinal extent: India lies between 68°7’E (Gujarat) and 97°25’E (Arunachal Pradesh) longitudes.

Question 3. State the boundary of India.
Answer:

The boundary of India on all sides are as follows—

1. North: The northern side of India is marked by the Himalayan mountains, China, Nepal and Bhutan.

2. West: India is bounded by Pakistan and the Arabian Sea on the west.

3. East: The eastern side of India is bounded by Myanmar, Bangladesh and the Bay of Bengal.

4. South: The peninsular region of India in the south is bounded by the Indian Ocean, the Arabian Sea and the Bay of Bengal. The island country of Sri Lanka lies south of India, separated by the Palk Strait and the Gulf of Mannar. The Maldives lie to the southwest of India.

“Location of India in geography Class 10”

Question 4. Mention the location of India with respect to the distance from the sea.
Answer:

Location of India with respect to the distance from the sea

India lies in south Asia. It is bounded by the Bay of Bengal in the east, the Arabian Sea in the west and the Indian Ocean in the south. Hence, it is called a peninsula. Being surrounded by the seas on three sides, no place in India is farther than 1700 km from the coast.

WBBSE Class 10 Geography Chapter 5 Question Answer

Question 5. Name the neighbouring countries of India.
Answer:

The neighbouring countries of India

The neighbouring countries of India are— China, Nepal and Bhutan in the north, Pakistan in the west, Afghanistan in the north-west, Myanmar and Bangladesh in the east and Sri Lanka in the south (separated from India by the Palk Strait and the Gulf of Mannar). The island of Maldives lies to the southwest of India.

Question 6. Discuss the importance of the geographical location of India.
Answer:

The importance of the geographical location of India

India lies in south Asia. The geographical location of the country influences its economy, security and livelihood of people.

1. The presence of seas on three sides of India provides access to international waterways and promotes foreign trade. The seas also act as a natural barrier and safeguard the security of the
mainland.

2. The mighty Himalayas in the north and the desert in the west also act as natural barriers and protect the country from foreign invasions. The mountain passes help in foreign trade.

3. The presence of seas on three sides of the country promotes fishing and related activities. It also influences the social life, food habits and economic status of the people.

4. The Himalayan region in the north encourages tourism and supplies raw materials for several industries like fruit processing, furniture making, paper, tea and construction.

WBBSE Class 10 Geography Chapter 5 Question Answer

Question 7. Mention the extent and population of India.
Answer:

Extent: The north-south extent of India is 3214 km and the east-west extent of India is 2933 km.

Area: Total area of India is about 32 lacks 87 thousand 263 sq. km. Of this, about 43 thousand sq. km. of area is occupied by China and Pakistan. According to size, India is the seventh largest country in the world (after Russia, Canada, China, USA, Brazil and Australia).

Population: India is the second most populated country in the world (after China). According to the 2011 census, the total population of India was 121 crores 1 lakh 93 thousand 422.

Question 8. Mention the importance of the peninsular location of India on the livelihood of people
Answer:

The importance of the peninsular location of India on the livelihood of people is—

1. The peninsular location of India promotes international trade through waterways from all three directions (east, west, and south).
2. The presence of seas on three sides of the country promotes activities like navigation and fishing.
3. The seas act as a natural barrier and protect the country from foreign invasions.
4. The northern part of India is connected to mainland of Asia. This helps in maintaining trade

“Administrative divisions of India WBBSE Class 10”

Question 9. Name the administrative divisions presently found in India.
Answer:

Presently, India is divided into types of administrative divisions- states and union territories. There are 28 states and 8 union territories in India.

State	Capital
1. Andhra Pradesh	Hyderabad
2. Arunachal Pradesh	Itanagar
3. Assam	Dispur
4. Bihar	Patna
5. Chhattisgarh	Raipur
6. Goa	Panaji
7. Gujarat	Gandhinagar
8. Haryana	Chandigarh
9. Himachal Pradesh	Shimla
10. Jharkhand	Ranchi
11. Karnataka	Bengaluru
12. Kerala	Thiruvananthapuram
13. Madhya Pradesh	Bhopal
14. Maharashtra	Mumbai
15. Manipur	Imphal
16. Meghalaya	Shillong
17. Mizoram	Aizawl
18. Nagaland	Kohima
19.0disha	Bhubaneswar
20. Punjab	Chandigarh
21. Rajasthan	Jaipur
22. Sikkim	Gangtok
23. Tamil Nadu	Chennai
24. Tripura	Agartala
25. Uttar Pradesh	Lucknow
26. Uttarakhand	Dehradun
27. West Bengal	Kolkata
28. Telangana	Hyderabad

 

 

Union Territories	Capital
1. Andaman and Nicobar Islands	Port Blair
2. Chandigarh	Chandigarh
3. Dadra and Nagar Haveli and Daman and Diu	Daman
4. Delhi	Delhi
5. Lakshadweep	Kavaratti
6. Puducherry (formerly known as Pondicherry)	Puducherry
7. Ladakh	Leh-Kargil
8. Jammu and Kashmir	Srinagar (May-October) Jammu (November-April)

 

Question 10. Discuss the standard meridian and standard time of India. OR, How does the longitudinal extent of India influence the standard time of the country?
Answer:

The standard meridian and standard time of India

India lies between the longitudes 68°7’E and 97°25’E. Therefore, the longitudinal extent is 97°25’E – 68°7’E = 29°18′ Each longitude or meridian has a different local time.

So, for ease of administration and time calculation, the meridian that passes through the centre of the country is chosen as the standard meridian, whose local time is considered the standard time of the country.

The 82°86’E meridian passes exactly through the centre of India. But for ease of calculation, the 82°30’E meridian is chosen as the standard meridian of India (passes through Allahabad). The local time of this standard meridian is considered as the standard time all over India.

Question 11. Why are Arunachal Pradesh and Meghalaya called so?
Answer:

The easternmost state of India was formerly known as the NEFA (North-East Frontier Agency). Being located at the eastern border, the first rays of sunlight could be seen from this region first in India as a whole. Hence, it was renamed Arunachal Pradesh.

The hilly regions of Khasi, Jaintia and Garo hills were included in the Union Territory of Meghalaya on 2 April 1970. The geographical location of the place influenced the weather conditions and generally kept the sky overcast with clouds.

Hence, it was named ‘Meghalaya'(the abode of clouds) by the famous geographer Dr S.P. Chatterjee. Later, on 21 January 1972, Meghalaya was given the status of a state.

“India’s physical environment Class 10 geography guide”

Question 12. What do you mean by ‘India subcontinent’?
Answer:

‘India subcontinent’:

The countries of India, Pakistan, Bangladesh, Maldives, Nepal, Bhutan and Sri Lanka together are known as the ‘Indian subcontinent’. These neighbouring countries have physical, geographical and cultural similarities. India is the largest country among them with respect to size and population.

It lies in the centre surrounded by the other five countries. Due to its size and location, India is the most influential country among them. Hence, the whole region is called the ‘Indian subcontinent’. Name the newly formed states of India and their capitals

authenticated by the Indian Constitution, more than 160 languages are spoken in the country. Language is a very important factor that influences the administration.

Thus, it plays an important role in state reorganisation. India was reorganised into 14 states and 6 Union Territories in 1956 based on the language popularly spoken over a large region.

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India Short Answer Type Questions

WBBSE Class 10 Geography Chapter 5 Question Answer

Question 1. Name the most and least populated states of India.
Answer:

According to the 2011 census, the most populated state of India is Uttar Pradesh (19.98 crores) and the least populated state of India is Sikkim (6.12 lakh).

Question 2. Presently, how many states and Union Territories are there in India?
Answer:

Presently, there are 29 states (including the newly formed states of Uttarakhand, Jharkhand and Telangana) and 7 Union Territories in India.

Question 3. Name the largest state and smallest state of India.
Answer:

The largest state of India is Rajasthan and the smallest state of India is Goa.

Question 4. Mention the latitudinal extent of the Indian mainland.
Answer:

The Indian mainland extends from 8°4’N in the south to 37°6’N in the north.

Question 5. Mention the longitudinal extent of India.
Answer:

The longitudinal extent of India is from 68°7’E in the west to 97°25’E in the east.

Question 6. From which erstwhile states the newly formed states of Uttarakhand and Chhattisgarh have been separated?
Answer:

Uttarakhand has been separated from the former state of Uttar Pradesh and Chhattisgarh has been separated from the former state of Madhya Pradesh.

Question 7. Mention the east-west and north-south extent of India.
Answer:

The east-west extent of India is 2933 km and the north-south extent of India is 3214 km.

Question 8. What are the length of India’s border and its coastline?
Answer:

The length of the border of India along all sides is about 15107 km. The length of the coastline of India including the mainland, Lakshadweep and Andaman and Nicobar Islands is about 7517 km.

Question 9. Name the largest and smallest Union Territory of India.
Answer:

The largest Union Territory of India in Jammu and Kashmir and the smallest one is Lakshadweep.

Question 10. Name the Union Territories of India.
Answer:

The Union Territories of India

The Union Territories of India are Andaman and Nicobar Islands, Chandigarh, Puducherry, Delhi, Lakshadweep and Dadra and Nagar Haveli and Daman, and Diu.

Question 11. Name the largest and smallest neighboring countries of India.
Answer:

The largest neighboring country of India is China and the smallest one is the Maldives.

Question 12. Which factors were given importance while state reorganization in India? OR, Mention two main bases of state reorganization of India?
Answer:

Different bases have been given importance during the time of state reorganization. Although the main basis of reorganization in 1956 was language, the other bases considered at different times are— culture, administrative advantage and skill, physical and geographical similarity, and economic stability.

Question 13. What are ‘The McMahon line’ and ‘Raddiffe line’?
Answer:

1. McMahon Line: The Indo-China border running from the eastern side of Bhutan to Arunachal Pradesh is known as the McMahon line.
2. Radcliffe Line: The Indo-Pakistan border in the northwestern part of India is known as the Radcliffe line.

“Geography chapter on India’s location and divisions WBBSE”

Question 14. Name two neighboring countries of India lying on the western side.
Answer:

Pakistan and Afghanistan are the two neighboring countries of India lying on the western side.

Question 15. Which Union Territory is recognized as the capital of two states of India?
Answer:

The Union Territory of Chandigarh is the capital of the states of Punjab and Haryana.

Question 16. What do you mean by SAARC?
Answer:

SAARC:

SAARC (South Asian Association for Regional Cooperation) is an organization formed for the political, economic, educational, cultural, scientific and technological, and recreational welfare of the member countries.

It was formed on 8 December 1985. Its headquarters is in Kathmandu, Nepal. The member countries are—India, Pakistan, Bangladesh, Nepal, Bhutan, Sri Lanka, Maldives, and Afghanistan.

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India If The Statement Is True,

Write True And If False Write False Against The Following

WBBSE Class 10 Geography Chapter 5 Question Answer

Question 1. The state reorganization in India occurred in the year 1950, on the basis of language.
Answer: False

Question 2. Rajasthan is the largest state in India.
Answer: True

Question 3. Jharkhand is the newest state in India.
Answer: False

Question 4. The Amindivi island lies within the Lakshadweep islands.
Answer: True

Question 5. The east-west extent of India is 2933 km.
Answer: True

Question 6. The north-south extent of India is lesser than the east-west extent.
Answer: False

Question 7. The Minicoy island is situated in the Manas Sarovar.
Answer: False

Question 8. The difference between the easternmost and westernmost longitudes of India is almost 29°18
Answer: True

Question 9. The local time of Allahabad is considered the standard time of India.
Answer: True

Question 10. The southernmost point of India is Kanyakumari.
Answer: False

Question 11. India was declared a sovereign, socialist, secular, democratic republic on 15 August 1947.
Answer: False

Question 12. The Tropic of Cancer passes through Bihar.
Answer: False

Question 13. NEFA has been renamed Mizoram.
Answer: False

Question 14. Jharkhand was given the status of a different state on the basis of regional cultural differences.
Answer: True

Question 15. India is the largest peninsular country in the world.
Answer: True

Question16. Goa is the smallest state in India.
Answer: True

Question 17. Sikkim was included as an Indian state in 1975.
Answer: False

Question 18. Goa was given the status of a state in 1989.
Answer: False

Question 19. ‘Meghalaya’ was named by Dr. S. P. Chatterjee.
Answer: True

Question 20. The newest state of India is Telangana.
Answer: True

 

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India Fill In The Blanks With Suitable Words

WBBSE Class 10 Geography Chapter 5 Question Answer

Question 1. India was declared a sovereign democratic republic in the year_______
Answer: 1950

Question 2. The State Reorganisation Commission was formed in_______
Answer: 1953

Question 3. The the_______islands lie on the Bay of Bengal.
Answer: Andaman and Nicobar Islands

Question 4. India is separated from Sri Lanka by the_______
Answer: Palk Strait

Question 5. The local time of_______ is considered the standard time of India.
Answer: Allahabad

Question 6. Presently, there are _______ Union Territories in India.
Answer: 8

Question 7. Rajasthan was previously known as _______
Answer: Rajputana

Question 8. Chennai was previously known as _______
Answer: Madras

Question 9. India is surrounded by oceans on _______ sides.
Answer: Three

Question 10. The Darjeeling Gorkhaland Territorial Administration is an _______body that looks after the administration of the hills of the Darjeeling district.
Answer: Autonomous

Question 11. The capital of Tripura is _______
Answer: Agartala

Question 12. The chief language spoken in Karnataka is_______
Answer: Kannada

Question 13. Indira point is also known as the _______
Answer: Pygmalion point

Question 14. _______ is considered the standard meridian of India.
Answer: 82°30’E

Question 15. _______ is the capital of both Andhra Pradesh and Telangana.
Answer: Hyderabad

Question 16. Kerala was given the status of a state in _______
Answer: 1956

Question 17. Delhi was declared as a Union Territory of India in _______
Answer: 1956

Question 18. The chief languages spoken in Telangana are_______ and _______
Answer: Telugu and Urdu

Geography Class 10 West Bengal Board

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India Answer In One Or Two Words

Question 1. When has India declared a sovereign, socialistic, secular democratic republic?
Answer: 26 January 1950.

Question 2. Which state’s capital is Bengaluru?
Answer: Karnataka.

Question 3. Which is the largest neighbouring country of India?
Answer: China.

Question 4. Name the capital of Dadra and Nagar Haveli and Daman and Diu.
Answer: Daman.

Question 5. Name the capital of Chattisgarh.
Answer: Raipur.

Question 6. Where is the headquarters of SAARt located?
Answer: Kathmandu in Nepal.

Question 7. Name the smallest neighbouring country of India.
Answer: Maldives.

Question 8. When was Telangana given the status of a separate state?
Answer: 2 June 2014.

Question 9. What was Karnataka previously known as?
Answer: Mysore.

Geography Class 10 West Bengal Board

Question 10. Which former state was broken into Gujarat and Maharashtra?
Answer: Bombay (presently known as Mumbai).

Question 11. Which languages are popularly used in Tripura apart from Bengali?
Answer: Kokborok and Manipuri.

Question 12. What is the India-Pakistan border popularly known as?
Answer: Radcliffe Line.

Question 13. Name the smallest Union Territory of India.
Answer: Lakshadweep.

Question 14. Which state was broken to form Uttarakhand?
Answer: Uttar Pradesh.

Question 15. How many languages have been accepted by the Constitution of India, to be spoken here?
Answer: 22.

Question 16. Name the capital of Uttarakhand.
Answer: Dehradun.

Geography Class 10 West Bengal Board

Chapter 5 India Physical Environment Topic 1 Location And Administrative Divisions Of India Match The Left column With The Right Column

1.

LeftColumn	Right Column
1. Andhra Pradesh	A.  Malayalam
2. Tamil Nadu	B. Kannada
3. Goa	C.  Tamil
4.  Karnataka	D.  Telugu
5.  Kerala	E.  Konkani

Answer: 1-D,2-C,3-E,4-B,5-A

2.

Left Column	Right Column
1. Telangana	A. Kohima
2. Jharkhand	B. Ranchi
3. Tripura	C. Dehradun
4. Uttarakhand	D Hyderabad
5. Nagaland	E. Agartala

Answer: 1-D,2-B,3-E,4-C,5-A

3.

Left Column	Right Column
1. Himachal Pradesh	A.  2000
2.  Chhattisgarh	B.  2014
3. Goa	C. 1971
4.  Telangana	D. 1963
5.  Nagaland	E. 1987

Answer: 1-C,2-E,3-E,4-B,5-D

 

Chapter 5 India-Physical Environment Topic 4 Climate Of India Long Answer Type Questions

Question 1. Discuss the climatic conditions in different seasons in India.
Answer:

The climatic conditions in different seasons in India

The climate of India can be classified into four seasons depending on the temperature, rainfall, atmospheric pressure, and wind direction prevailing over a time period,

1. Winter season (December-February):

1. During this time the sun’s rays fall at a high angle in the southern hemisphere. The northern hemisphere receives slanting rays from the sun, whose angle of incidence is low.

2. The dry and cold winds generated from the high-pressure regions of Central Asia blow over India are northeast monsoon winds. These winds move towards the low-pressure regions over the Indian Ocean.

3. The average temperature in northern India remains about 10°-15°C. The temperature gradually increases towards the south and reaches about 25°C in Tamil Nadu.

Read and Learn Also WBBSE Solutions for Class 10 Geography and Environment

4. Rainfall is caused in the northern and north-western regions due to Western disturbances.
The coastal regions of Tamil Nadu also receive rainfall due to the northeast monsoon winds. The rest of the country generally remains dry.

2. Summer season (March-May):

1. During this season with the gradual movement of the sun towards the north the sun’s rays fall at a high angle in the northern hemisphere. As a result from March onwards, the temperature of India starts rising.

2. By the month of May, the sun’s rays fall almost vertically over the Tropic of Cancer. Thus, the temperature of the northern hemisphere rises considerably. The average temperature of Madhya Pradesh and Gujarat rises to 38°-40 °C. The temperature in the desert region of Rajasthan reaches about 48 °C.

3. The hot dry wind called ‘Loo’ is experienced in the northwestern part of India due to very high temperatures.

4. Low-pressure cells develop over many regions, which leads to the generation of tropical storms. These storms are locally known as ‘Kalbaisakhi’ in West Bengal, ‘Aandhi’ in Uttar Pradesh, ‘Bordoichila’ in Assam, ‘Mango showers’ in Kerala and ‘Cherry Blossoms’ in Karnataka.

5. These storms and associated rainfall may suddenly reduce the temperature by 7-8 °C.

3. Rainy season or the monsoon season (June-September): The deep low-pressure cells created over the landmass of India during summer, attract the moist southwest monsoon winds from the Indian Ocean. These winds bifurcate into two branches before entering India—

1. The Arabian Sea branch: This branch of the southwest monsoon, collects a huge amount of moisture from the Arabian Sea and moves towards the Indian landmass.

They are obstructed by the Western Ghats, where they provide profuse rainfall on the western slopes. The eastern slopes lie on the leeward side of the Western Ghats and hence receive less rainfall. This turns the western part of the Deccan plateau into a rain shadow area.

 

2. The Bay of Bengal branch: This branch of the southwest monsoon winds collects large amounts of moisture from the Bay of Bengal and enters India from the eastern side.

They are obstructed by the Eastern Himalayas and the hilly region of the northeast. There they provide huge amounts of rainfall.

Mawsynram situated on the southern slope of the Khasi hills of Meghalaya receive the highest rainfall in the world (1187 cm). These winds gradually move westward and provide rainfall in Manipur, Meghalaya, Assam, West Bengal, Bihar, Uttar Pradesh, and other states of northwestern India.

4. Autumn season or the season of retreating monsoon (October- November): During this time the sum apparently starts shifting southwards beyond the equator. Thus, the high-pressure condition develops over landmass in the northern hemisphere and the low-pressure condition develops over the Indian Ocean.

The retreat of the monsoon winds sometimes causes tropical cyclones and sudden rainfall in the eastern coastal regions of India. In West Bengal, the cyclonic storm is locally known as ‘Ashwiner Jhor’.

“WBBSE Class 10 Geography Chapter 5 Climate notes”

Question 2. Explain the influence of monsoons on the climate of India.OR, Discuss the characteristics of the seasons of India as influenced by the monsoon winds.
Answer:

The influence of monsoons on the climate of India

The climate of India is strongly influenced by the monsoon winds. The southwest monsoon winds blow during the summer and the northeast monsoon winds blow during the winter.

1. Influence of the southwest monsoon:

1. During summer, the southwest monsoon winds originate over the Indian Ocean and blow towards the low-pressure cell developed over the northwestern region of India.

2. These moisture-laden winds help to set in the rainy season in the country.

3. India receives about 67-72% of its total annual rainfall due to the southwest monsoon. Rainfall occurs in profuse amounts in Assam, Mizoram, Meghalaya, Eastern Himalayan region, Terai region, and Andaman and Nicobar Islands.

2. Influence of the north-east monsoon:

1. During winter, the cold dry winds blow from the high-pressure regions of Central Asia towards the low-pressure cell developed over the Indian Ocean.

2. These winds lower the air temperatures to a great extent. Temperatures in Jammu and Kashmir, Himachal Pradesh, Uttar Pradesh and other northern states fall as low as -10° to -40 °C. 0 The winds being very cold, have very less capable of holding moisture. Thus, they cause no rainfall.

Power in India to a great extent dependent on monsoon rains. If there is insufficient rainfall the reservoirs remain full of water, which helps in hydroelectric power generation.

3. Unpredictable onset and retreat of monsoon: The before-time arrival or late retreat of the southwest monsoon results in a longer rainy season. This may lead to floods. On the other hand, late arrival or early retreat of the monsoons leads to a shorter rainy season. This may cause the soil to dry up and bead to droughts.

4. Seasons according to the monsoon winds: The climate of India can be classified into four seasons depending on the arrival and retreat of the monsoon winds.

They are-

1. Pre-arrival period of southwest monsoon or the summer season.
2. Season of southwest monsoon or the rainy season.
3. Retreat of the southwest monsoon, or the autumn season.
4. Onset of north-east monsoon, or the winter season.

Question 3. Discuss the influence of the southwest monsoons on India.
Answer:

The influence of the southwest monsoons on India

1. The positive influences of the southwest monsoon winds on India are-

1. Influence on climate: India mostly lies in the tropical-subtropical region, which is very hot. But the southwest monsoon winds provide sufficient rainfall to the landmass, which helps to reduce the general temperature conditions. Hence, India enjoys a hot and humid climate.

2. Influence on irrigation: Water for irrigation also depends upon the availability of water from the dams and reservoirs. In years of sufficient rainfall the area covered by irrigation increases or vice versa. In years of insufficient rainfall, the height of the underground water table falls leading to a shortage of water in the wells, tanks, and tube wells.

3. Influence on hydroelectric power generation: Generation of hydroelectric monsoon rains. If there is insufficient rainfall the reservoirs remain full of water, which helps in hydroelectric power generation.

3. Influence on agriculture: India is an agro-based country. About 70% of India’s population is directly or indirectly dependent on agriculture. The southwest monsoon winds provide sufficient rainfall for agriculture to be conducted properly. The crop calendar of India is dependent on the monsoon rainfall.

4. Influence on agro-based industries: The agro-based industries of India, like cotton textile, sugar, jute textile, tea and coffee, etc. are influenced by the southwest monsoon. The raw materials of these industries are dependent on the rainfall provided by the southwest monsoon.

5. Influence on forests: The forests or natural vegetation are directly related to the climate of a place. The distribution of rainfall in India decides the types of forests found in different regions of India.

6. Influence on the economy: Agriculture, industrial development, the lifestyle of the people, etc. are dependent on the southwest monsoon winds and the rainfall they provide. In general, the whole economy of the country is influenced by the monsoon winds.

2. The negative influences of the south-west monsoon winds are-

1. Floods and droughts: The whimsical and unpredictable nature of the southwest monsoon winds often bring hazards in India. Early onset and late retreat of the monsoon winds bring in too much rainfall and may cause floods. On the other hand, late arrival and early retreat of monsoon winds may cause droughts due to less rainfall.

2. Expensive irrigation system: Agriculture is dependent on the rainfall provided by the southwest monsoon. But the whimsical nature of the monsoon winds may lead to crop failures. Hence, irrigation facilities have to be arranged to assure the yield of crops. This is very expensive and needs a lot of maintenance.

3. Crop failures and loss of life and property: Frequent floods and droughts in India often cause crop failures and result in loss of life and property. Often food grains, pulses, oilseeds, and other crops have to be imported to meet the demands of the country. This imposes a negative effect on the economy of the country.

Question 4. Discuss any three factors that control the climate of India. OR, Discuss the factors that control the climate of India.
Answer:

The factors that control the climate of India are as follows-

1. Monsoon winds: The climate of India is influenced by two opposite monsoon winds—The hot wet southwest monsoon in summer and the dry cold northeast monsoon in the winter.

2. South-west monsoon winds:

1. During summer a deep low-pressure cell develops over central and north India. This draws the moist southwest monsoon winds from the Indian Ocean into the country. The rainy season commences, providing rainfall almost over the whole of India, except in a few places,

2. About 67-72% of rainfall in India occurs due to the southwest monsoon.

3. North-east monsoon winds:

1. During winter, a high-pressure cell develops over Central Asia, from where cold and dry winds rush towards the Indian Ocean, passing over the landmass of India,

2. The general temperature of the country decreases,

3. Generally the winds are dry. But before leaving the country, the winds collect some moisture from the Bay of Bengal and cause rainfall on the Coromandel coast of Tamil Nadu.

Depending on the monsoon winds, the climate of India can be classified into four seasons—

1. The pre-monsoon or the summer season,
2. The onset of the southwest monsoon or the rainy season,
3. The retreat of the south-west monsoon or the autumn season,
4. The onset of the northeast monsoon or the winter season.

2. Latitudinal extent: The Tropic of Cancer divides the country into almost two equal halves. The southern part lies in the tropical region while the northern part lies in the sub-tropical region. The Himalayan region lies in the temperate region. Hence, the temperature of the northern region is lower than that of the southern region.

3. Location of the Himalayas and the Western Ghats: The mighty Himalayas prevent the moisture-laden southwest monsoon winds from escaping northwards. They help to cause rainfall in the country. Similarly, the Western Ghats lie across the direction of the Arabian Sea branch of the southwest monsoon and cause rainfall on its western slope. The Himalayas also prevent cold Siberian winds from entering India in winter.

4. Altitude: Temperature decreases by 6.4 °C for every 1 km or 1000 m rise in altitude (lapse rate). Thus, the peaks of the Himalayan mountains remain snow-covered throughout the year due to the high altitude. For this reason, Ooty is a cooler place in spite of lying closer to the equator than New Delhi.

5. Distance from the sea: The long coastline of India brings a huge area in the west, south, and east under the influence of the sea.

“Climate zones of India Class 10 Geography”

Question 5. Differentiate between ‘Loo’ and ‘Aandhi’.
Answer:

The differences between ‘Loo’ and ‘Aandhi’ are as follows-

Point of difference	LOO	Aandhi
Region influenced	Loo blows predominantly in the desert region of north-western Rajasthan, the adjacent areas of the desert, and in the drier states of north-western India.	Aandhi blows in the north-western region of the Sutlej-Ganga plains.
Nature	Loo is a strong, hot, dry wind.	Aandhi is a strong stormy dusty wind.
Time	Loo blows during summer.	Aandhi blows during the end of spring.
Temperature	The temperature of the wind varies between 45° and 50 °C.	The temperature of the wind varies between 32° and 35 °C.
Period	Loo blows during noon in the hot desert or semi-desert regions.	Aandhi blows for a small period in the afternoon.
Sky condition	Loo does not cause the sky to become dark.	Aandhi causes the sky to become dark and reduces visibility.
Effects	The hot and dry loo causes the leaves of plants to dry up and turn brownish.	Aandhi deposits layers of dust on the leaves of plants and hampers photosynthesis.

 

WBBSE Solutions For Class 10 Geography Chapter 5

Question 6. Discuss the influence of monsoon winds on the livelihood of people in India.
Answer:

The influence of monsoon winds on the livelihood of people in India

The monsoons impose a lot of influences on the livelihood of the people in India.

1. Cultivation of crops: More than 70% of the people of India are dependent on agriculture directly or indirectly. Agriculture is dependent on monsoon rains. Hence, people who depend on agriculture are dependent on monsoon.

2. Agro-based industries: The agro-based industries acquire their raw materials from agricultural products. They are indirectly dependent on monsoons for their production and economic growth.

3. Forest: The monsoon rains have helped in the growth of dense evergreen forests in the foothills of the Himalayas and the Western slopes of the Western Ghats. Deciduous forests grow in regions of moderate to high rainfall. These forests yield valuable timber and other forest products.

4. Economic development: The economic development of the country is much dependent on the monsoons. Sufficient rainfall helps in agricultural and industrial development, while droughts and floods cause crop failures and loss of life and property.

5. Foreign exchange: Crops like tea, Jute, sugarcane, etc. are dependent on monsoons. The export of tea, jute products, sugar, etc. helps India to earn a lot of foreign exchange. Thus, it is indirectly dependent on the monsoons.

Question 7. What are the characteristics of the climate of India?
Answer:

The characteristics of the climate of India are-

1. Seasons: The climate of India is influenced by the two oppositely blowing monsoon winds, i.e., the south-west monsoon winds help in the classification of Indian climate into four seasons—Winter (December- February), Summer (March-May), Monsoon or Rainy season (June-September) and Autumn (October-November).

2. Oppositely blowing winds: The direction from which the winds blow in the summer season (southwest) is reversed in the winter season (northeast).

3. Hot wet summers and cool dry winters: The moist southwest monsoon winds provide sufficient rainfall during late summer and the rainy season. The northwest monsoon winds are generally dry and do not provide rainfall except for the Coromandel coast of Tamil Nadu. Thus, the summers are hot and wet while the winters are cool and dry.

4. Orographic rainfall: The southwest monsoon winds collide with the mighty Himalayas on the north and the Western Ghats along the western coast. Thus, they provide orographic rainfall in the foothills of the Himalayas and the western slopes of the Western Ghats.

5. Unpredictable rainfall: The whimsical nature of the monsoon winds make the occurrence of rainfall unpredictable. In some years rains come early and retreat late, while in some years the rains arrive late and retreat early. Thus, the monsoon winds sometimes cause floods and sometimes lead to droughts.

6. Diverse climate: The northern part of India is surrounded by landmasses. Hence, it experiences extreme and continental climates. The southern part is surrounded by oceans on three sides (west, south, and east). Hence, it experiences a moderate climate.

7. Cyclones: During the autumn season, the eastern and the western coastal regions experience cyclonic storms and rainfall. During the winter season, the Western disturbances cause cyclonic rainfall in the northwestern part of India. The temperature drops to a great extent and the hilly regions experience snowfall.

Question 8. Discuss the climatic regions of India. Or, Classify India according to climatic regions and discuss any three of them.
Answer:

The climatic regions of India

A region having similar conditions of temperature, pressure, humidity, rainfall, wind, etc. is known as a climatic region. Following the climatic classification of Koppen, India has been classified-

Climatic region	Amongst influenced	Characterise features
1. Tropical very wet monsoon region	Coastal areas of Maharashtra, Karnataka, Goa, and Kerala, western slopes of the Western Ghats, Meghalaya, Mizoram, Manipur, Cachar district of Assam, Lakshadweep, Andaman, and Nicobar Islands.	1. Average annual temperature 18°-29 °C. 2. Average annual rainfall 300 cm.
2. Tropical Savanna region	Gujarat, Maharashtra, Chhattisgarh, Jharkhand, Andhra Pradesh, Odisha.	1. Average Annual temperature 15″-30 °C. 2. Average annual rainfall 50-100 cm.3. Very hot summers and cool winters.
3. Tropical dry summer and wet winter region	Coromandel coast of south-eastern India.	1. Average annual temperature 20°-30 °C. 2. Average annual rainfall 100-150 cm. 3. Dry summer (Eastern Tamil Nadu) and wet winter.
4. Tropical semi-desert and sub-tropical steppe region	Rain shadow areas of the Western Ghats, eastern Rajasthan, and southwest Pujnab.	1. Average annual temperature 10°-40  °C 2. Average annual rainfall 50-75 cm.
5. Hot desert region	Western Rajasthan.	1. Average annual temperature 5°-48  °C. 2. Average annual rainfall 12.5 cm-30 cm. 3.  Extreme continental climate. The diurnal and annual range of temperature is very large.
6. Temperate mild summer and wet winter region	Sikkim, Arunachal Pradesh, northeastern Assam.	1. Average annual temperature 20″-35 °C. 2. Average annual rainfall above 300 cm.
7. Wet sub-tropical monsoon region (dry winter)	Plains of northern India.	1.  Average annual temperature 5 °-30  °C. 2. Average annual rainfall is 200 cm in the east and 50 cm in the west. 3. Rainfall occurs mostly in summer.
8. Cold mountainous region	High mountains of the Western Himalayas.	1. Average annual temperature is 15 ‘C in summer to less than 0 °C in winter. 2. Average annual rainfall 50-75 cm. 3. Very cold throughout the year and snowfall in winter.

 

 

“Impact of monsoon on Indian climate WBBSE”

Question 9. Discuss the influences of the Himalayas on the climate of India.
Answer:

The influences of the Himalayas on the climate of India

The Himalayas stand on the northern margin of India like a huge and mighty wall. It influences the climate of India in the following ways-

1. Protects from the severe cold: The Himalayan mountains prevent the chilling polar winds coming from Siberia from entering the country and making the climate very cold and chilling.

2. Helps in causing rainfall: The Himalayas stand like a barrier against the southwest monsoon winds. The moisture-laden winds strike against the mountains and cause orographic rainfall. India receives about 67 72% of its total annual rainfall from the southwest monsoon.

3. Creates desert climate: The Himalayas prevent the moisture-laden southwest monsoon winds from escaping the country. Thus, it plays a vital role in the creation of deserts in Gobi and Taklamakan in Central Asia.

4. Reduces the effects of the Western disturbances: The Himalayas keep the effects of the Western disturbances limited to the northwestern part of the country.

It may be mentioned that, during the winter season, the northeast monsoon winds pass through the gap between the Eastern Himalayas and the Purvanchal mountains and decreases the temperature of the Brahmaputra Valley in Assam considerably.

5. Moderate climate: The places lying at high altitudes in the lap of the Himalayas enjoy cool climates throughout the year. Snowfall in the winter makes the place more attractive for tourism.

Question 10. What are the causes of the diversity in the climate of India?
Answer:

The causes of the diversity in the climate of India

The climate of India is diverse and different in different parts of the land at different times of the year. The causes of diversities are-

1. Latitudinal extent:

The main landmass of India extends from 8° N in the south to 37° N in the north. Thus, it spreads for about 29° of latitude. The southern part of India experiences a hot wet equatorial climate, the central part experiences a tropical climate, and the northern part experiences a subtropical and temperate climate.

2. Presence of mountains:

1. The Himalayan mountains in the north play a vital role in influencing the climate of India. During summer, they stop the moist southwest monsoon winds from escaping to Central Asia and cause rainfall in India.

During winter, they prevent the chilling polar winds coming from Siberia from entering India, thus keeping the climate of the country comparatively warmer and more comfortable.

2. The Western Ghats and the Eastern Ghats along the western and eastern coasts of India cause rainfall on their windward sides. Being higher the Western Ghats stop more amounts of moisture-laden winds and receive sufficient rainfall. The leeward side of these mountains lying in the Deccan plateau makes the region comparatively drier. This is a rain shadow region.

3. The Aravalli range lying parallel to the direction of the Arabian Sea branch of the southwest monsoons fails to stop the moisture-laden winds. Thus, the vast region of Rajasthan remains devoid of rainfall and makes Thar a desert.

3. Altitude: India is a country of diverse landforms. Hence, even though Agra and Darjeeling lie almost on the same latitude, Darjeeling is much cooler than Agra due to altitude [Temperature falls by 6.4 °C for every 1000 m rise in altitude]. Different places in the country have different temperature conditions for similar reasons.

4. Peninsular shape: The peninsula of India is triangular in shape (southern part). This makes the land narrow towards the south and brings the land under the influence of the Bay of Bengal in the east, the Indian Ocean in the south, and the Arabia Sea in the west. Thus, the southern part of India experiences a moderate maritime climate while the northern part experiences an extreme continental climate.

5. Distance from the sea: The places in southern India are not too far away from the coast. Hence, they enjoy moderate or maritime climates. But the places in northern India (e.g. Delhi, Jaipur, Lucknow, etc.) are far away from the coastal region. Hence, they have no influence on the sea and experience extreme or continental climates.

6. Oppositely blowing monsoon winds: India experiences two oppositely blowing monsoon winds at different times of the year. During summer, the monsoon winds blow from the southwest and during winter they reverse their direction and blow from the northeast. This causes the formation of seasons.

7. Temporary shift of the pressure belts: The sun’s apparent northward and southward movement cause temporary shifting of the pressure belts northwards and southwards by 5°-10°. This leads to temporary changes in climate conditions.

Question 11. Discuss the influence of topography, jet stream, tropical cyclones, Western disturbances, El Nino and La Nina on the climate of India.
Answer:

The climate of India is influenced by several factors. Some of them are—

1. Topography or relief: The topography of India is different in different regions. This influences the climate to a great extent.

1. The mighty Himalayas standing at the northern margin of the country stop the southwest monsoon winds from escaping northwards and helps to cause rainfall. Also, they stop the cold Siberian polar winds from entering the country and help to keep the climate warm and comfortable.

2. The Western Ghats stand against the Arabian Sea branch of the southwest monsoon and help to cause heavy rainfall on its western slopes. The presence of these mountains makes the eastern slopes or the Deccan plateau region a rain shadow area.

3. The north-south alignment of the Aravalli range fails to stop the moisture-laden monsoon winds.

4. In southern India, the region should have been hot due to the latitudinal position. But, high altitude in many places makes them mildly cold. E.g. Ooty being located at an altitude of 2240 m, remains cold throughout the year.

5. The Garo, Khasi and Jaintia hills in north-east India receive immense rainfall on their windward sides. This makes Cherrapunji in Meghalaya the rainiest place in the world.

2. Jet stream: The very speedy winds generated in the upper atmosphere is known as the jet stream. It influences the climate of India in two ways—

1. Westerly jet: The westerly jet blows over the sub-tropical region during the winter season. This creates high-pressure conditions over the northwestern part of India.

This condition causes the northeast monsoon winds to blow from the landmass toward the Indian Ocean. The westerly jet is responsible for Western disturbances, winter rainfall in certain regions, and snowfall in the hilly regions.

2. Easterly jet: The easterly jet blowing from the tropical region causes low-pressure conditions over the Indian landmass. This helps to attract the moisture-laden southwest monsoon winds and marks the onset of the rainy season in the country.

3. Tropical cyclones: During the autumn, when the temperature of the sea surface rises too high, low-pressure conditions are created. This leads to the formation of cyclones in the Bay of Bengal, the Indian Ocean, and the Arabian Sea.

These are called tropical cyclones, which influence the climate of the coastal regions of India. The cyclones cause profuse rainfall and stormy conditions in India.

4. Western disturbances: Although the Western disturbances develop over the Mediterranean Sea, they are drawn eastwards by the westerly jet stream. These disturbances cause rainfall in the northwestern part of India and snowfall in the Western Himalayas.

5. El Nino and La Nina: El Nino is a southward moving warm current that develops along the coasts of Ecuador and Peru in the eastern Pacific Ocean in December-January.

El Nino causes floods or droughts in the tropical region. The countries of south-east Asia receive very less rainfall due to El Nino and droughts are created. After the effects of El Nino recedes, calm weather conditions prevail. This is known as La Nina. This causes enough rainfall in India. The effects of La Nina may last for 1-3 years.

Question 12. Discuss the effects of monsoon winds natural vegetation and agriculture in India.
Answer:

Effects of monsoon winds on soil, natural vegetation, and agriculture are discussed below—

1. Effects of monsoon winds on soil: The amount of rainfall regulates the level of fertility of the soil. In areas receiving heavy or very heavy rainfall, the minerals and soil nutrients are washed down. Thus, infertile soils like laterite and red soil are formed.

In regions receiving moderate to heavy rainfall, the soil is sandy. In regions of medium rainfall, the amount of vegetation growth is maximum. This makes the soil rich in nitrogen and humus content.

2. Effect of monsoon winds on natural vegetation: The amount of rainfall received in an area is the deciding factor of the type of natural vegetation to be found there.

Wet deciduous forests are found in regions of heavy rainfall while dry deciduous forests are found in regions of low rainfall. In regions of scanty or no rainfall, there is thorny, bushy, or no vegetation cover at all.

3. Effects of monsoon winds on agriculture: Agriculture in India is highly dependent on monsoons. Depending on the amount of rainfall received, methods of dry farming or wet farming are implemented.

In regions of scanty rainfall, agriculture is practiced with the help of irrigation. The crop calendar of India is also determined by the monsoons. E.g. Depending on the amount of rainfall received, some regions grow rice, some grow wheat, some grow tea and coffee while some grow millet crops like Jowar, Bajra, and ragi.

Chapter 5 India-Physical Environment Topic 4 Climate Of India Short Explanatory Answer Type Questions

Question 1. Why Is the climate of India called a ‘monsoonal climate’? Slstiat’ OR, Why is India called the country of monsoonal climate?
Answer:

India is called the country of monsoonal climate for the following reasons-

1. Monsoon comes from the Arabic Word ‘mausinV, meaning season. In India, seasonal reversals of winds are seen.

2. The southwest monsoon winds cause wet summers and the northeast monsoon winds cause dry winters in India.

3. All the seasons found in India are related to the coming or retreating of the monsoon winds. Eg. Pre-arrival of south-west monsoon winds-Summer, the arrival of south-west monsoon winds-Rainy season, reversal and retreat of south-west monsoon winds- Autumn, the arrival of north-east monsoon winds-winter.

4. About 72% of the total annual rainfall occurring in India comes from the monsoon winds.

5. The rainy season is included in the summer season, thus broadly there are four seasons.

Question 2. Classify the main seasons of India.
Answer:

The main seasons of India are classified as follows

The climate of India can be classified into four main seasons based on the temperature, atmospheric pressure, rainfall, winds, etc. prevailing over a period of time.

 

Seasons	Months
1. Winter or northeast monsoon	December to February
2. Summer	March to May
3. South-west monsoon or rainy season	June to September
4. Autumn or retreating south-west monsoon	October to November

 

“Climate change effects in India Class 10 Geography”

Question 3. Why does rainfall occur In northwest India during winter?
Answer:

During winter, the dry and cold northeast monsoon winds blow over India. As it originates over cold land so this season is generally dry.

However, in some years temperate cyclones generated over the Mediterranean sea reach the north-western part of India with prevailing winds. These cyclonic winds gather moisture from the Arabian Sea and cause rainfall in that region.As these winds come from the western direction, they are called Western disturbances. The amount of rainfall gradually decreases eastwards.

Question 4. Why are floods and drought prevalent in India?
Answer: In India, the monsoon winds are responsible for both drought and flood.

The causes behind the prevalence of floods and drought in India are as follows—

Causes of drought:

1. Lesser rainfall than normal.
2. Late arrival of monsoon winds.
3. Early retreat of monsoon winds.
4. A number of dry days in the rainy season.
5. Excessive heat due to El Nino.

Causes of the flood:

1. Heavy rainfall due to the southwest monsoon winds.
2. Late retreat of the monsoon winds.
3. Early arrival of the monsoon winds.
4. Continuous heavy rainfall for many days.
5. Overflowing of rivers and dams.

Question 5. Why does the Coromandel coast of ‘ Tamil Nadu receive rainfall twice a year? OR, What is the cause of rainfall in the Coromandel coast in winter?
Answer:

The Coromandel coast of Tamil Nadu receives rainfall twice a year.

1. During summer, the region receives rainfall from the southwest monsoon winds along with the whole country.

2. During winter, cold and dry winds blow from the northeast and generally cause no rainfall. But while leaving the eastern coast, the winds gather sufficient moisture from the Bay of Bengal and re-enter the landmass near the Coromandel coast.

These moisture-laden winds provide heavy rainfall on the Coromance coast of Tamil Nadu before they finally leave the landmass. Example-Chennai in Tamil Nadu receives 43 cm of rainfall from June-September but about 87 cm of rainfall from October- December.

Question 6. Classify the regions of India according to the amount of rainfall received
Answer:

A rainfall region refers to a region that receives more or less the same amount of rainfall on average.

Based on this, India can be sub-divided into five rainfall regions—

 

WBBSE Solutions For Class 10 Geography Chapter 5

Rainfall	Area	Average annual rainfall
Very heavy rainfall region	Western slopes of the Western Ghats, Eastern Himalayas, Mizoram, northern West Bengal, Andaman, and Nicobar Islands.	> 200 cm
Heavy rainfall region	Bihar, eastern Uttar Pradesh, Uttarakhand, Jharkhand, Chhattisgarh, hilly region of Himachal Pradesh, Odisha, the southern part of West Bengal.	100-200 cm
Medium rainfall region	Punjab, Haryana, eastern Rajasthan, Karnataka, Tamil Nadu, Maharashtra.	60-100 cm
Low rainfall region	Rain shadow area of the Western Ghats, western parts of Punjab and Haryana, central Rajasthan.	20-60 cm
Scanty rainfall region	Desert region of Rajasthan, Ladakh, north-western Gujarat.	< 20 cm

 

Question 7. Which regions of India receive excessive rainfall and why?
Answer:

About 72% of the total annual rainfall of India comes from the monsoon winds. But, rainfall is not evenly distributed over India. There are two regions in the country that receive excessive rainfall.

They are-

1. The western slopes of the Western Ghats: The Arabian Sea branch of the southwest monsoon is obstructed by the western slopes of the Western Ghats. Hence, this region receives a huge amount of orographic rainfall.

2. Eastern and northeastern India: The Bay of Bengal branch of the southwest monsoon enters India along the east and moves northward. They hit the Eastern Himalayas and the Purvanchal mountains and cause heavy rainfall in the northeastern and eastern regions.

The regions receiving heavy rainfall are—Assam, Arunachal Pradesh, Meghalaya, Manipur, Nagaland, Mizoram, Tripura, and the northern part of West Bengal.

Question 8. Why do some regions in India receive scanty rainfall?
Answer:

India receives most of its rainfall due to the southwest monsoon winds, but the distribution of rainfall is not even all over the country. There are three regions in India that receive scanty rainfall-

1. Western Rajasthan and Northwestern Gujarat.
2. Ladakh plateau of Ladakh.

Western Ghats and Eastern Ghats.

1. Western Rajasthan and north-western Gujarat:

1. Some winds from the Arabian Sea branch of the southwest monsoon blow over Kathiawar in Gujarat and escape to the northwest, as there are no maintains to stop them.

2. The Aravalli range of Rajasthan lies parallel to the wind direction and fails to stop the monsoon winds from escaping northward. Thus, these regions receive scanty rainfall.

2. Ladakh plateau Ladakh: The Ladakh plateau is an intermontane plateau surrounded by high mountains on all sides. Thus, moisture-laden winds cannot cross the mountains to provide rainfall to the region. As a result, the plateau remains dry.

3. The rain shadow area lying between the Western Ghats and the Eastern Ghats:
The southwest monsoon winds give heavy rainfall on the windward slope of the western ghats. When the winds reach the leeward side, they don’t have enough moisture to provide rainfall. Hence, the leeward side of the Western Ghats is a rain shadow area and receives scanty rainfall.

“Understanding Indian monsoon patterns Class 10”

Question 9. Why are winters dry in India?
Answer:

The retreating monsoon or the northeast monsoon prevails in India before the onset of the winter.

1. These winds blow from land towards the sea, and cannot collect moisture in their course of movement. Thus, they are dry.
2. These winds are very cold and the water-holding capacity of these winds is very low. Thus, they fail to cause rainfall.
3. high pressure exists over the landmass and low pressure exists over the surrounding water bodies. Thus, winds blow offshore.

All these causes make the winters dry in India. As an exception, a small branch of the retreating monsoon collects moisture from the Bay of Bengal and provides heavy rainfall to the Coromandel coast of Tamil Nadu before finally leaving the landmass.

Question 10. What are the causes of the formation of the Thar desert?
Answer:

The causes of the formation of the Thar desert

India receives most of its rainfall from the southwest monsoon winds. But the distribution of rainfall is not even all over the country. The amount of rainfall decreases from east to west. The western part of Rajasthan receives very scanty or almost no rainfall.

This is due to the following reasons—

1. The Arabian Sea branch of the southwest monsoon blows over the Kathiawar region of Gujarat and escapes towards the northwest. There are no high mountains to obstruct these winds.

2. The Aravalli range of Rajasthan lies parallel to the direction of the monsoon winds and cannot stop them from escaping northwards.

3. The high temperature of the region increases the water-holding capacity of the winds and reduces the chances of rainfall. All these cause extreme scarcity of rainfall and lead to the formation of the Thar desert.

Question 11. Why do desert regions have extreme summers and winters?
Answer:

The desert regions have extreme summers and winters due to the following reasons—

1. The desert regions are covered with sand and rocks, which can absorb and release heat very quickly. Thus, they become very hot during the daytime, especially in summer, and very cold during the night, especially in winter.

2. The sky remains clear throughout the year in the desert remains. This helps in the fast escape of terrestrial radiation.

3. The desert atmosphere lacks the presence of water vapor. Water vapor helps to absorb heat and keeps the atmosphere warm. The absence of this helps the desert to cool down very fast during the night. The difference in the average temperature of summers and winters in deserts may be as large as 30-40°C.

Question 12. What is a rain shadow region? Give examples. OR, Where does the rain shadow area lie in India?
Answer:

Rain shadow region:

The moisture-laden winds being obstructed by a highland shed heavy rains on the windward slope. In this way, they become lighter and rise to cross the mountains.

As the winds reach the other side of the mountains, they do not have enough moisture to provide rainfall to the leeward slope. Also, as the winds move downward, the winds get warmer, and the water-holding capacity increases. Hence, this slope remains comparatively drier than the windward slope.

This is called the rain shadow region.

1. The windward side or the western slope of the Western Ghats receives heavy, rainfall from the Arabian Sea branch of the southwest monsoons. But the eastern slope receives no or scanty rainfall and turns into a rain shadow region.

2. The southern slope of the Garo and Khasi hills in Meghalaya receives extremely heavy rainfall. Mawsynram near Cherrapunji on that slope receives the highest rainfall in the world (1187 cm). But, the Shillong plateau lying on the northern slope or the leeward side of the mountains receives only 159 cm of rainfall annually. Hence, Shillong is a rain shadow area.

Question 13. Why does the southwest monsoon cause rainfall in India?
Answer:

The south-west monsoon causes rainfall in India for the following reasons—

1. During summer, especially during May, a deep low-pressure cell is developed over the Northern plains. This is a main driving force that draws the moisture-laden southwest monsoon winds from the Indian Ocean into the Indian landmass.

2. The winds are onshore winds, which collect a lot of moisture while crossing the surrounding seas. In the extreme north, the Himalayas act as a climatic barrier preventing these winds from crossing over to the other side. Thus, the southwest monsoon winds shed all their moisture over the Indian landmass and in turn lower the temperature.

Question 14. How can floods and drought be controlled in India?
Answer:

Flood controlling measures:

1. Construct strong dams along the banks of the rivers.

2. Monitoring the amount of rainfall and volume of water in the river channel regularly.

3. Maintaining the depth of the river channels by dredging out silt.

4. Construction of houses in high places if the region is flood prove.

5. Proper system to forecast flood conditions.

6. Construction of reservoirs in the upper course of the rivers, so that excessive water flowing through the rivers in the rainy season can be stopped from causing floods.

7. Prevention of soil erosion so that soil does not run off into river channels and decreases the depth.

Drought-controlling measures:

1. Proper use and utilization of rainwater, flowing water, and groundwater without any misuse.

2. Rainwater harvesting to provide water in the dry seasons.

3. Cultivation of drought-resistant crops.

4. Spread irrigation for agriculture, especially through pipelines in dry regions to prevent evaporation.

Question 15. Discuss the causes of floods in India.
Answer:

The causes of floods in India are—

1. The whimsical and unpredictable nature of southwest monsoons-

1. Torrential showers for a few hours continuously may cause floods.

2. Medium to heavy showers for a long time continuously may also cause floods.

3. Early onset and late retreat of monsoon increase the volume of rainfall received. Thus, also leads to floods.

2. Too much siltation in the river bed reduces the depth of the channel. This reduces the water-holding capacity of the rivers. Hence, floods may occur even due to medium rainfall.

3. Release of excess water from dams behind rivers leads to a sudden increase of water level in the rivers and leads to floods.

4. Cyclones developed in coastal areas lead to floods due to sudden rises in the water level of the seas and the devastating action of the waves.

5. In mountainous areas, landslides may block the path of rivers, thus flooding adjacent areas.

6. In desert regions, the dry channels of rivers and streams get filled up with sand and get blocked. Hence, even a small shower of rainfall can cause floods.

7. Some rivers tend to change their courses, leading to floods.

Question 16. causes of drought in
Answer:

The issues of drought in India can be broadly classified into two types—

1. The whimsical and unpredictable nature of southwest monsoon.
2. Deforestation.

1. The whimsical and unpredictable nature of the southwest monsoon: India receives 67-72% of its total annual rainfall from the southwest monsoon. But-

1. Late-onset and early retreat of the monsoon winds cause less amount of rainfall and may result in drought.

2. Rainfall may not occur every day during the rainy season. The sudden interval of rainfall for a long period during the rainy season is known as the ‘break of monsoon’. This may cause a shortage of water, drying up of the soil, lowering of the underground water table, and failure of crops. Thus, droughts may occur.

2. Deforestation:

1. Cutting down trees expose the soils to the scorching heat of the sun in summer. The soil moisture gradually dries up and the underground water table goes down. This may lead to conditions of drought.

2. Absence of trees reduces the level of transpiration considerably. This makes the air dry. Thus, it tends to draw out underground water in the form of vapor and lowers the water table. If such a situation prevails for a long time, droughts may result.

Question 17. Discuss the role of forests in the climate of India.
Answer:

The role of forests in the climate of India

The forests of India play a vital role in influencing the climate of the country.

1. Forests lead to a huge amount of transpiration and recharge the air with water vapor. Hence, the atmospheric condition near forest areas is humid.

2. A dense canopy of leaves of trees in a forest prevents sunlight from reaching the forest floor directly and drying up the soil moisture.

3. The transpired water increases the moisture content of the atmosphere and aids in rainfall.

4. The forest cover helps to reduce the temperature of the place considerably. The north-western region and the Deccan plateau region of India have less tree cover, hence they are comparatively warmer than the forested regions.

Question 18. Why Is India known as the land of a variety of climates?
Answer:

India is a country with a variety of landforms, which influences the climate of various regions of the country.

1. Difference in temperature: Different temperatures prevail in different parts of the country in different seasons. Example— The summer temperature of the Thar desert reaches as high as 5CTC, while the winter temperature of Ladakh drops to as low as-40°C.

2. Range of temperature: The average annual range of temperature in northern India is about 20-25°C, while that in the south is only 4-6°C.

3. Difference in rainfall: Heavy rainfall in the southern slopes of the Garo and Khasi hills makes Mawsynram near Cherrapunji the rainiest place in the world. On the other hand, the lack of rainfall in north-western regions makes Thar in Rajasthan a desert.

4. Wind: India’s climate is mostly influenced by the southwest monsoon winds in the summer and northeast monsoon winds in the winter. Apart from these, some local winds also influence the climate. E.g. Loo, Aandhi, and Nor’westers in summer. ‘Ashwiner Jhor’ in autumn and Western disturbances in winter make India’s climate full of varieties.

Question 19. Discuss the characteristic features monsoon climate in India.
Answer:

The monsoon climate prevails in India due to the influence of the monsoon winds.

The characteristic features of the climate are-

1. The most significant characteristic feature of India’s climate is the reversal of wind direction. The monsoon winds blow from just opposite directions in the summer and winter seasons

2. The cold dry north-east monsoon winds blowing in the winter drop the average temperature prevailing in the country.

3. The southwest monsoon winds blow from the sea to the land and hence are moisture-laden. They provide about 72% of the total annual rainfall that India receives.

4. The monsoon winds are unpredictable in nature. Hence, sometimes the rainy season sets in fast and stays for a long time, and sometimes it sets in late and leaves early. This whimsical nature of the winds influences the climate and agriculture of the country.

Question 20. Discuss the nature of rainfall in India.
Answer:

The nature or characteristics of rainfall in India are-

1. Uneven distribution of rainfall: Rainfall is not evenly distributed all over India. The Eastern Himalayas, western slopes of Western Ghats, and Andaman and Nicobar Islands receive ample rainfall, whereas, Rajasthan, Jammu and Kashmir, Punjab, and Gujarat receive scanty rainfall.

2. Seasonal rainfall: India does not receive rainfall evenly throughout the year. 72% of the total annual rainfall occurs in the monsoon or rainy season, 10% in summer, 15% in autumn, and 3% in winter.

3. Uncertain rainfall: The amount of rainfall provided by the monsoon winds is uncertain. In some years, excessive rainfall may lead to floods, while in some years droughts may result due to scanty rainfall.

4. Break of monsoon: Long intervals may occur in the rainfall during the monsoon season due to the shift of the monsoon trough.

Question 21. How do the monsoon winds influence the economy of the country?
Answer:

The economy of India is largely influenced by the monsoon winds-

1. Influence on agriculture: The Indian economy is basically an agro-based economy. Agriculture is largely dependent on monsoon winds. The timely onset of monsoons and sufficient rainfall help in the production of crops. But late arrival of the monsoons or insufficient rainfall may lead to crop failures and droughts.

2. Influence on irrigation: Water for irrigation also depends upon the availability of water from the dams and reservoirs. In years of sufficient rainfall the area covered by irrigation increases or vice versa. In years of insufficient rainfall, the height of the underground water table falls leading to a shortage of water in the wells, tanks, and tube wells.

3. Influence on hydroelectric power generation: Generation of hydroelectric power in India to a great extent dependent on monsoon rains. If there is sufficient rainfall the reservoirs remain full of water, which helps in hydroelectric power generation.

4. Influence on industries: The agro-based industries are largely dependent on the monsoon winds for acquiring their raw materials. For example—The growth of jute, sugar cane, and cotton requires ample rainfall. Timely and sufficient rainfall will lead to a huge production of crops. Thus, the required amounts of raw materials can be supplied to the related industries. But delay in rainfall or a lesser amount of rainfall may lead to less production of crops. Hence, the industries will suffer.

5. Influence on economic development: Excessive rainfall from the southwest monsoons may result in floods and lack of rainfall may lead to droughts. Both situations may lead to loss of life and property, crop failures, food shortages, and hamper livelihood. Thus, the economy may suffer as a whole.

WBBSE Solutions For Class 10 Geography Chapter 5

Question 22. Classify the climate of India into seasons.
Answer:

The climate of India is influenced by the onset and retreat of the monsoon winds.

Based on this, the climate of India can be classified into our seasons—

1. The pro-arrival time of the southwest monsoon in the summer season,

2. The arrival of the monsoon winds or the rainy season.

3. The reversal of the southwest monsoon winds, or the autumn season.

4. The onset of the northeast monsoon winds or the winter season.

“Seasonal variations in Indian climate WBBSE”

Question 23. Why do we find a desert west of the Aravaili range? OR, How has a desert been formed on the western side of the Aravaili range?
Answer:

The Bay of Bengal branch of the southwest monsoon provides huge amounts of rainfall in the eastern part of the country, which goes on reducing towards the west.

By the time the winds reach Rajasthan, they become dry and cannot provide rainfall any further. Moreover, the Arabian Sea branch of the monsoon winds blows parallel to the Aravaili range in Rajasthan. They are not obstructed by the Aravaili range and hence provide no rainfall. Thus, a desert has been formed on the western side of the Aravaili range.

Question 24. Why do the western slopes of the Western Ghats receive orographic rainfall?
Answer:

The Arabian Sea branch of the southwest monsoon collides with the western slopes of the Western Ghats. These moisture-laden winds cause heavy rainfall in this region. The main cause of this rainfall is a collision of the moisture-laden winds with the western slopes of the high mountains. Thus, it is said that the Western Ghats receive orographic rainfall.

Question 25. How do the Himalayan mountains influence the climate of India?
Answer:

The Himalayan mountains influence the climate of India in the following ways-

1. The mountains stand across in the path of the southwest monsoon winds and prevent escaping towards the north. The moisture-laden winds collide with the southern slopes of the mountains and cause orographic rainfall. This rainfall is responsible for helping India to grow a large number of crops.

2. The mountains stop the chilling winds coming from Central Asia from entering the Indian landmass. This keeps the temperature of the northern part of the country less cold and more comfortable in the winter season.

Question 26. Why are the monsoon winds also called seasonal winds?
Answer:

The word monsoon derives from the Arabic word ‘Muslim’ meaning season. The monsoon winds blow from different directions in different seasons.

During summer, the winds blow from the southwest direction, while during winter they blow from the northeast direction. Due to this seasonal reversal of the direction of winds, the monsoon winds are also known as seasonal winds.

Question 27. Why are the southwest monsoon winds moist?
Answer:

The southwest monsoon winds generate over the Indian Ocean. While blowing towards India, they cross the Arabian Sea and the Bay of Bengal before entering the landmass. They collect enough moisture while blowing over these water bodies. Thus, the southwest monsoon winds become moist.

Question 28. Why are ‘Kalbaisakhi’ storms also called ‘Nor’westers’?
Answer:

During the summer season, the landmass of India, especially the north-western region becomes very hot. This creates a deep low-pressure cell over the Chotanagpur plateau.

This low pressure induces the formation of cyclones. As a result coastal regions of West Bengal experience thunderstorms and heavy rainfall. Locally, these thunderstorms are known as ‘Kalbaisakhi’, but since they are caused by winds coming from the north-western direction, they are also called ‘Nor’westers’.

Question 29. Describe the influence of jet stream on monsoon winds.
Answer:

The influence of jet stream on monsoon winds are-

1. The generation of monsoon winds is influenced by the jet stream.
2. The jet stream is responsible for the arrival of etc. remains uniform and is called a climatic region.

Chapter 5 India Physical Environment Topic 4 Climate Of India

Short Answer Type Questions

Question 1. Which regions receive rainfall in winter in India?
Answer:

The regions receiving rainfall in winter in India are—

1. North-west India and
2. The southern part of the eastern coastal plain or the Coromandel coast of Tamil Nadu.

Question 2. Which regions in India receive more than 200 cm of rainfall on average?
Answer:

Western slopes of the Western Ghats, Eastern Himalayas, Mizoram, North Bengal, Andaman, and Nicobar Islands.

Question 3. Name two storms occurring in two different seasons.
Answer:

1. Thunderstorms called Kalbaisakhi or Nor’westers, bring rainfall to regions of West Bengal in summer.
2. Thunderstorms called Ashwiner Jhor, occur in West Bengal in autumn.

Question 4. What do you mean by ‘Ashwiner Jhor’?
Answer:

Ashwiner Jhor

During autumn in India, tropical cyclones cause storms and rainfall in coastal parts of West Bengal due to lower air pressure over the Bay of Bengal. These storms are devastating and cause loss of life and property. They are called ‘Ashwiner Jhor’.

Question 5. What do you mean by climatic region?
Answer:

Climatic region

1. The region in which various elements of weather and climate, like temperature, rainfall, humidity, etc. remain uniform is called a climatic region. monsoon winds in India.

2. Sometimes the winds reach the Indian landmass before time while sometimes they are delayed.

3. The northward movement of the southwest monsoon is influenced by the jet stream. Unless the jet stream moves away from the plains of northern India, the southwest monsoon winds cannot blow over land.

Question 6. What are monsoon winds?
Answer:

Monsoon winds

The monsoon winds are the most important seasonal winds that flow over the earth, especially over the countries of Southeast Asia. The word monsoon comes from the Arabic word ‘Muslim’, meaning ‘season’.

These winds blow in particular seasons, hence are called monsoon winds. India experiences two opposite monsoon winds in different seasons. The southwest monsoon winds in the summer and the northeast monsoon winds in the winter.

Question 7. Name some regions receiving scanty rainfall in India.
Answer:

The regions receiving scanty rainfall in India are-

1. Desert and semi-desert regions of Rajasthan and Gujarat.
2. Ladakh plateau of Kashmir.
3. Eastern slopes of the Western Ghats, Karnataka plateau.
4. Shillong in the northern part of the Meghalaya plateau.

Question 8. What are the causes of heavy rainfall in Meghalaya?
Answer:

The causes of heavy rainfall in Meghalaya

The Bay of Bengal branch of the southwest monsoon winds enters Bangladesh and moves northwards. Before reaching the Himalayas in the north and the mountainous region in north-east India, these winds are being obstructed by the Garo, Khasi, and Jaintia hills of the Meghalaya plateau. This causes heavy rainfall in Meghalaya.

Question 9. Name the region receiving the heaviest rainfall in the world.
Answer:

The southern slopes of the Meghalaya plateau is the region receiving the heaviest rainfall in the world. Mawsynram, situated south of the Meghalaya plateau near Cherrapunji is the wettest place in the world. This place receives an average annual rainfall of more than 1187 cm.

WBBSE Solutions For Class 10 Geography Chapter 5

Question 10. What do you mean by drought?
Answer:

Drought

The environmental condition created due to scanty or lack of rainfall is called drought. According to the Indian Meteorological Department (IMD), meteorological drought occurs when the seasonal rainfall received in a region is less than 25% of its long-term average rainfall. The drought is classified as moderate if the rainfall deficit is 26-50% and severe drought when the deficit exceeds 50% of the normal long-term average rainfall. Drought results in severe scarcity of water for agriculture, irrigation, and drinking.

Question 11. Name the place of the highest and lowest rainfall in India.
Answer:

1. Highest rainfall: Mawsynram near Cherrapunji on the southern slope of the Khasi hills is the region with the highest rainfall in India. Also, the western slopes of the Western Ghats and the foothills of the Eastern Himalayas receive heavy rainfall.

Lowest rainfall: Marusthali or the desert region of Rajasthan receives the lowest rainfall in India. The Ladakh plateau of Jammu and Kashmir is also a region of scanty rainfall.

Question 12. Name two states receiving snowfall in winter.
Answer:

The states of India receiving snowfall in winter are-

1. Jammu and Kashmir and
2. Himachal Pradesh.

Question 13. What are Nor’westers or Kalbaisakhi?
Answer:

Nor’westers or Kalbaisakhi

In coastal regions of West Bengal, a severe thunderstorm generates in the afternoon during the summer season. This may bring heavy rainfall. This is called Kalbaisakhi. As the winds come from the north-western direction, they are also called Nor’westers.

Question 14. What are Mango showers?
Answer:

Mango showers

The thunderstorms that occur in the states of Kerala, Karnataka, and also some parts of Tamil Nadu and Puducherry are called Mango showers. These showers arrive in late April and May and bring rainfall. The showers aid in ripening mangoes, hence the name.

Question 15. What do you mean by the ‘burst of monsoon’?
Answer:

Burst of monsoon

In India, during late summer, a deep low-pressure cell or a depression develops over the northwestern part of India. This depression draws winds from the high-pressure region over the Indian Ocean. The winds are divided into two branches-the Arabian Sea branch and the Bay of Bengal branch and enter India from the southwest as the southwest monsoon. These moisture-laden winds suddenly cause thunderstorms and bring heavy rainfall. This onset of the monsoon is known as the ‘burst of monsoon.

Question 16. Why is the monsoon wind unpredictable in nature?
Answer:

India receives about 72% of its total annual rainfall from the southwest monsoon. But these winds in some years come before time, causing heavy rainfall and sometimes retreating too early leaving a deficit of rainfall. Sometimes they are the cause of floods while sometimes they cause drought. Thus, the monsoon winds are highly unpredictable in nature.\

Question 17. Write a short note on Western disturbances.
Answer:

Western disturbances

The cyclonic winds that originate over the Mediterranean Sea and reach the north-western part of India with the prevailing wind during the winter are known as Western disturbances.

They are influenced by the westerly winds in the temperate region. The Western disturbances cause rainfall and snowfall in Jammu and Kashmir, Himachal Pradesh, Punjab, Uttarakhand, and Uttar Pradesh.

Question 18. Why is the western part of Rajasthan Known as Marusthali?
Answer:

The western part of Rajasthan receives very little rainfall. Here, rainfall is highly variable in nature. The region is so arid that it is difficult to support plant or animal life over there. Hence, it is called ‘Marusthali’, the land of the dead.

Question 19. Which regions of India receive rainfall in winter?
Answer:

1. Coromandel or Tamil Nadu coast receives winter rainfall due to the northeast monsoon.
2. North-western parts of India receive winter rainfall due to Western disturbances.

Question 20. What is a ‘Jet stream’?
Answer:

Jet stream

The jet stream is a fast-flowing, narrow meandering air current blowing from west to east in the upper part of the Troposphere. The speed of the winds in a jet stream usually ranges from 190-400 km/hr. The jet stream influences the climate of India.

Question 21. What is Loo’?
Answer:

Loo

The hot, dusty, and dry summer wind called Loo blows over the western Indo-Gangetic Plain particularly in Punjab, Haryana, Rajasthan, Uttar Pradesh, Delhi, and North Gujarat during the day. It is especially strong in May and June. The Loo blows at a speed of 30-35 km/hr and due to its very high temperatures of 45-50° C often leads to fatal heatstrokes.

Question 22. Name some regions in India that come under the influence of Loo.
Answer:

The western Indo-Gangetic Plain particularly Punjab, Haryana, Rajasthan, Uttar Pradesh, Delhi, and North Gujarat come under the influence of Loo. The eastern part of Bihar, Jharkhand, and the Purulia district of West Bengal also experience Loo.

Question 23. What is Aandhi?
Answer:

Aandhi

The violent dust squalls that occur in the afternoon during summers in the northwestern part of India, especially in the states of Rajasthan, southern Punjab, western UP, and Delhi are called Aandhi. The speed of these winds is about 50-60 km/hr.

Question 24. Why does the Malabar coast receive heavy rainfall?
Answer:

The Arabian Sea branch of the southwest monsoon reaches the Malabar coast on 1st day of June. It hits the western slopes of the Western Ghats. This causes heavy rainfall (above 200 cm) along the Malabar coast.

Question 25. Why does the coastal region of Tamil Nadu receive rainfall twice a year?
Answer:

1. The southwest monsoon gives heavy rainfall to the coastal region of Tamil Nadu in summer.
2. In autumn, while the southwest monsoon winds retreat, they collect a lot of moisture from the Bay of Bengal. These moisture-laden winds re-enter the land near the Coromandel coast of Tamil Nadu and provide sufficient rainfall before finally leaving the land.

Question 26. List the causes of floods in India.
Answer:

The causes of floods in India

1. Onset of monsoons before time.
2. Continuation of rainfall for a long period.
3. Heavy rainfall over a region at a stretch.
4. Sudden cloud bursts.

Question 27. What are the causes of drought in India?
Answer:

The causes of drought in India

1. Late coming of the southwest monsoon.
2. Before time retreat of the monsoon winds.
3. Lack of sufficient moisture in the air.

Question 28. What do you mean by ‘break of monsoon’?
Answer:

Break of monsoon

During the southwest monsoon season there are periods when the monsoon trough shifts from the Gangetic plains towards the foothills of the Himalayas. This leads to a sharp decrease in rainfall over a large part of the country. Such a situation is known as the ‘break of monsoon’.

Chapter 5 India Physical Environment Topic 4 Climate Of India

Multiple Choice Type Questions

Question 1. The main characteristic feature of the climate of India is—

1. Change of seasons
2. High temperature
3. Heavy rainfall
4. Severe cold

Answer: 1. Change of seasons

Question 2. Which of the following is a local wind in India?

1. Monsoon winds
2. Loo
3. AshwinerJhor
4. Cyclone

Answer: 2. Loo

Question 3. The ‘burst of monsoon’ occurs in—

1. Rainy season
2. Summer
3. Autumn
4. Winter

Answer: 2. Summer

Question 4. ‘AshwinerJhor’ occurs in—

1. Autumn
2. Monsoon
3. Winter
4. Summer

Answer: 1. Autumn

Question 5. Rainfall occurs twice a year in—

1. North-eastern India
2. Southern Himalayas
3. Coastal regions of Tamil Nadu
4. Western Ghats

Answer: 3. Coastal regions of Tamil Nadu

Question 6. Western disturbances occur in—

1. Winter
2. Summer
3. Monsoon
4. Spring

Answer: 1. Winter

Question 7. The word ‘Muslim’ means—

1. Season
2. Rainfall
3. Wind
4. Snowfall

Answer: 1. Season

Question 8. The type of rainfall that mostly occurs in India is—

1. Convectional rainfall
2. Orographic rainfall
3. Cyclonic rainfall
4. None of these

Answer: 3. Orographic rainfall

Question 9. The ‘burst of monsoon’ brings the onset of—

1. Summer
2. Rainy season
3. Winter
4. Autumn

Answer: 2. Winter

Question 10. The general climate of southern India is—

1. Hot and dry
2. Wet and cold
3. Moderate
4. Temperate

Answer: 3. Moderate

Question 11.’Mango showers’ occur in—

1. North India
2. East India
3. South India
4. West India

Answer: 3. South India

Question 12. Which of the following is a rainshadow area in India?

1. Chotanagpur plateau
2. The western slope of the Western Ghats
3. Shillong plateau
4. The south-eastern coast of Tamil Nadu

Answer: 3. Shillong plateau

Question 13. A city in India experiencing extreme climate is—

1. Cuttack
2. Kolkata
3. Mumbai
4. Amritsar

Answer: 4. Amritsar

Question 14. The climate of India is influenced by the—

1. North-east monsoon
2. South-east monsoon
3. North-west monsoon
4. South-west monsoon

Answer: 4. South-west monsoon

Question 15. In India, the least amount of rainfall is received by—

1. Thar desert in Rajasthan
2. Plains of Gujarat
3. Ladakh
4. Coastal plains

Answer: 1. Thar desert in Rajasthan

Question 16. The storms that occur in the afternoon during the summer season in West Bengal are called—

1. ‘AshwinerJhor’
2. Loo
3. Mango showers
4. Kal Baishakhi

Answer: 4. ‘AshwinerJhor’

Question 17. In India, the cool mountainous climate is found in the—

1. North
2. South
3. North-west
4. East

Answer: 1. North

Question 18. In West Bengal, the cyclonic storms generated in the Bay of Bengal in October- November are known as—

1. Nor’westers
2. Western disturbances
3. Loo
4. ‘AshwinerJhor’

Answer: 4. ‘AshwinerJhor’

Question 19. A rainshadow area in South India is—

1. Ladakh
2. Shillong
3. Eastern slope of the Sahyadri
4. Shimla

Answer: 3. Eastern slope of the Sahyadri

Question 20. In India, the highest average rainfall is received in the—

1. North-west
2. South
3. North-east
4. West

Answer: 3. North-east

Question 21. The mountains that influence the climate of India are—

1. Aravalli range
2. Himalayan range
3. Western Ghats
4. Garo hills

Answer: 2. Himalayan range

Question 22. The monsoon winds enter the mainland of India in—

1. May
2. June
3. July
4. August

Answer: 2. June

Question 23. The Western disturbances cause snowfall in—

1. Delhi
2. Jammu and Kashmir
3. Punjab
4. Haryana

Answer: 3. Jammu and Kashmir

Question 24. The monsoon winds prevail for the least duration in—

1. North-east India
2. North-west India
3. West India
4. South India

Answer: 2. North-west India

Question 25. In India, the cyclones that occur in the autumn season are generated in the—

1. Arabian Sea
2. Gulf of Khambat
3. Bay of Bengal
4. Indian Ocean

Answer: 3. Bay of Bengal

Question 26. Western disturbances arise in the—

1. Arabian sea
2. Red sea
3. Mediterranean sea
4. Bay of Bengal

Answer: 3. Mediterranean sea

Question 27. Which of the following districts of West Bengal receives the lowest amount of rainfall?

1. Darjeeling
2. Nadia
3. Purulia
4. Bankura

Answer: 3. Purulia

Question 28. The local name for the first storm and rainfall of the monsoon season in Assam is—

1. Bordoichila
2. Nor’westers
3. Loo
4. Mango showers

Answer: 1. Nor’westers

Question 29. In India, the steppe climate is found in—

1. Southern Bengal
2. Eastern Tamil Nadu
3. Eastern Rajasthan
4. Western Karnataka

Answer: 3. Eastern Rajasthan

Question 30. Western disturbances help in—

1. Cultivation of rabi crops
2. Cultivation of plantation crops
3. Cultivation of Kharif crops
4. None of these

Answer: 1. Cultivation of rabi crops

Question 31. According to the latitudinal extent, the northern part of India lies in the—

1. Frigid zone
2. Hot Temperate zone
3. Torrid zone
4. Cool temperate zone

Answer: 2. Hot Temperate zone

Question 32.’Aandhi’ is a—

1. Dust storm
2. Hot wind
3. Cyclonic rainfall
4. Cold wind

Answer: 1. Dust storm

Question 33. In India, El Nino leads to—

1. Flood
2. Drought
3. Heat waves
4. Cold waves

Answer: 2. Drought

Question 34. The drought of 2014 in India was the result of—

1. El Nino
2. La Nina
3. Western disturbances
4. None of these

Answer: 1. El Nino

Question 35. The south-west monsoon winds are a result of—

1. Westerly jet stream
2. Easterly jet stream
3. El Nino
4. Ocean currents

Answer: 2. Easterly jet stream

Question 36. Change of seasons does not occur in the

1. Tropical monsoon climate region
2. Equatorial climate region
3. Hot desert climate region
4. China’s type of climate region

Answer: 2. Equatorial climate region

Chapter 5 India Physical Environment Topic 4 Climate Of India

If The Statement Is True, Write True And If False Write False Against The Following

Question 1. The general climate of India is Temperate Monsoon type.
Answer: False

Question 2. The Arabic word ‘Muslim’ means season.
Answer: True

Question 3. Mango showers occur in West Bengal.
Answer: False

Question 4. Loo is a wet cold wind.
Answer: False

Question 5. The southeast monsoon winds influence rainfall in India.
Answer: False

Question 6. Rainfall occurs twice a year on the Coromandel coast.
Answer: True

Question 7. Western disturbances cause rainfall and snowfall during winter.
Answer: True

Question 8. Temperature is low at the poles because the angle of incidence of sun’s rays is very low.
Answer: True

Question 9. The thunderstorms occurring in West Bengal during autumn are called ‘Kalbaisakhi’.
Answer: False

Question 10. Shillong is a rain shadow area.
Answer: True

Question 11. If rainfall occurs less than 75% of the normal rainfall in a particular region, the condition is said to be a drought.
Answer: True

Question 12. The presence of seas on three sides of peninsular India gives the long coastline of the country a moderate climate.
Answer: True

Question 13. The dust storm occurring in April-May in northwest India is called Loo.
Answer: False

Question 14. Mediterranean sea in winter is called The thunderstorms that occur at the coastal plains during autumn are called Kalbaisakhi.
Answer: False

Question 15. The monsoon winds are a larger edition of land breeze and sea breeze.
Answer: True

Question 16. The Shillong plateau and the northern part of the Meghalaya plateau is a rain shadow areas.
Answer: True

Question 17. The central region of the plateau of southern India represents the rain shadow area of the Western Ghats.
Answer: True

Question 18. The wind that blows according to the seasons is called ‘Kalbaishakhi’.
Answer: False

Question 19. A severe low pressure develops over the northwestern part of India during summer.
Answer: True

Question 20. Loo is a hot dry wind.
Answer: True

Question 21. The rain shadow area of India is known as the ‘famine-prone region of India’.
Answer: True

Question 22. The average annual rainfall is very low in Uttar Pradesh.
Answer: False

Question 23. Kerala and Goa receive moderate rainfall.
Answer: False

Question 24. During October-November, a low pressure develops over the Indian Ocean due to vertical rays of the sun on the Tropic of Cancer.
Answer: False

Question 25. Maximum rainfall in India occurs from May-June.
Answer: False

Question 26. The Thunderstorms occur as a result of the influence of the westerly winds over the ‘Ashwine Jhor’.
Answer: False

Chapter 5 Indian-Physical Environment Topic 4 Climate Of India Fill In The Blanks With Suitable Words

Question 1. India is a country of______ climate.
Answer: Monsoons

Question 2. In India, the maximum rainfall occurs in the ______
Answer: Mawsynram

Question 3. Rainfall occurs twice a year in the coastal regions of ______
Answer: Tamil Nadu

Question 4. The climate of India is influenced by the ______ winds.
Answer: Monsoon

Question 5. The thunderstorms occurring in southern India during the summer season are called ______
Answer: Mango showers

Question 6. ‘Monsoon’ comes from the Arabic word ______
Answer: Mausim

Question 7. The ______ monsoon winds are cold and dry.
Answer: North-east

Question 8. ______ is a cold desert in India.
Answer: Ladakh

Question 9. ______ are periodic winds that blow over India.
Answer: Monsoon

Question 10. ______ winds influence the weather of a small region.
Answer: Local

Question 11. The Mango showers are known as in______ Karnataka.
Answer: Cherry blossoms

Question 12. In India, the ______ monsoon winds blow from October-December.
Answer: North-east

Question 13. The ______ season prevails over India during October-November.
Answer: Autumn

Question 14. The Western disturbances cause ______ in north India.
Answer: Precipitation

Question 15. The Kalbaisakhi comes from the northwest, hence it is called the ______
Answer: Nor’westers

Question 16. The cyclonic winds prevailing in autumn are called ______
Answer: Ashwiner Jhor

Question 17. ______ is a flood prove region in India.
Answer: Assam valley

Question 18. The ______ jet streams help in the generation of the southwest monsoon winds.
Answer: Easterly

Question 19. In India, steppe climate prevails in ______
Answer: Eastern Rajasthan

Question 20. The dust storms occurring in Rajasthan are known as______
Answer: Aandhi

Question 21. The______ winds are a larger edition of the land breeze and sea breeze.
Answer: Monsoon

Question 22. The first rainfall occurring at the beginning of the rainy season is called the ______
Answer: Burst of monsoon

Question 23. The hot winds blowing over Uttar Pradesh, Bihar, and Rajasthan during summer are called ______
Answer: Loo

Question 24. The monsoon winds are ______
Answer: Seasonal

Question 25. About______ % of total rainfall in India occurs in the rainy season.
Answer: 72

Question 26. The temperature of North India is ______ than that of South India in summer, keeping the weather calm.
Answer: Lower

Question 27. The ______ generating in the Pacific Ocean
Answer: La Nina

Chapter 5 Indian-Physical Environment Topic 4 Climate Of India Answer In One Or Two Words

Question 1. Which place in India receives the highest rainfall?
Answer: Mawsynram.

Question 2. Which is the main controlling factor of India’s climate?
Answer: Monsoon winds.

Question 3. Name a rain shadow area in India.
Answer: Shillong.

Question 4. Which wind blows over India in winter?
Answer: North-east monsoon winds.

Question 5. What is the pre-monsoon wild wind known as in Assam?
Answer: Bordoichila.

Question 6. When do Western disturbances occur?
Answer: Winter.

Question 7. What kind of climate prevails in the Ladakh plateau?
Answer: Cold desert climate.

Question 8. What is Aandhi?
Answer: A dust storm occurs in summer in Rajasthan.

Question 9. Name the thunderstorm that occurs in West Bengal in summer.
Answer: Kalbaisakhi.

Question 10. What kind of climate prevails in India?
Answer: Tropical monsoon climate.

Question 11. What does the term monsoon mean?
Answer: Season.

Question 12. Which region in India receives rainfall twice a year?
Answer: Coromandel coast in Tamil Nadu.

Question 13. Which region in India receives very less rainfall?
Answer: Thar desert in Rajasthan/Dras in Ladakh.

Question 14. What are thunderstorms that occur in autumn called?
Answer: Ashwiner Jhor.

Question 15. Which mountains help to cause rainfall from the southwest monsoon winds?
Answer: Himalayas.

Question 16. Where does El Nino originate?
Answer: Over the South Pacific Ocean.

Question 17. Which slope of the Himalayas is comparatively warmer?
Answer: Southern slope.

Question 18. Which season is mostly influenced by Western disturbances?
Answer: Winter season.

Question 19. Which season is mostly influenced by the Easterly jet?
Answer: Rainy season.

Question 20. Over which sea of India originates more cyclones?
Answer: Bay of Bengal.

Question 21. Which winds cause maximum rainfall in India?
Answer: South-west monsoon winds.

Question 22. Which is the hottest month in India?
Answer: May.

Question 23. When does Ashwiner Jhor occur?
Answer: October-November.

 

Chapter 5 Indian-Physical Environment Match The Left Column With The Right Column

 

1.

Left Column	Right Column
1.  Kalbaisakhi	A.  North-west India
2. Aandhi	B. Brahmaputra Valley
3. Bordoichila	C. Odisha and the coastal region of West Bengal
4. Mango showers	D. Lower Ganga plains
5. Ashwiner Jhor	E. Kerala

Answer: 1-C,2-D,3-E,4-A,5-B

2.

Left Column	Right Column
1.  India	A.  Hot dry wind
2.  Mawsynram	B. Highest rainfall in the world
3.  Autumn	C.  Identified climate regions of India
4. Loo	D. Monsoon climate
5. Koppen ‘	E. Retreat of south-west monsoon monsoon

Answer: 1-B,2-C,3-A,4-D,5-E

3.

Left Column	Right Column
1.  Easterly jet	A. North-east monsoon
2.  Westerly jet	B.  Thar desert
3. Burst of monsoon	C.  South-west monsoon
4. Western disturbances	D. Rainfall and snowfall in winter
5. Desert climate	E. Onset of the rainy season

Answer: 1-D,2-A,3-E,4-C,5-B

4.

Left Column	Right Column
1. Heavy rainfall	A.  Sandy soil
2. Hot and less rainfall	B.  Clayey soil
3. Wet climate	C. Drought in India
4. Seasonal rainfall	D.  Red soil
5. El Nino	E. Deciduous trees

Answer: 1-D,2-A,3-E,4-B,5-C

 

Chapter 5 India-Physical Environment Topic 5 Soils In India Long Answer Type Questions

Question 1. Discuss the various causes of soil erosion.
Answer:

The causes of soil erosion can be broadly classified into two types-

1. Natural causes
2. Manmades causes

Read and Learn Also WBBSE Solutions for Class 10 Geography and Environment

1. Natural causes:

1. Landform: The rate of soil erosion is greater in hilly regions than on plains due to the slope. The soil is not very deep and mature on hills and plateaus. Hence, it is easily washed down by rainwater or slips along the slope by gravitational force.

2. Storm: Strong winds and storms may uproot big trees and make the soil loose and easily eroded. Also, open or exposed lands are prone to soil erosion by the action of wind.

3. Nature of rainfall: Rainfall is directly related to soil erosion. If rainfall occurs with small drops and a short period, the level of soil erosion is less. But if there is heavy rainfall with big drops for a long period of time, the level of soil erosion is greater. Open land is more prone to erosion by splashing of rainwater than land covered with vegetation.

4. Wind: In deserts and arid regions where there is no or very less vegetation, the wind causes erosion over huge areas.

5. Flowing water: In hilly regions, the rainwater from higher altitudes comes down along the slopes of hills in numerous thin streams. These streams cause erosion of the slopes as they flow down, e.g. gully erosion, rill erosion, ravine erosion, etc.

2. Man-made Causes:

1. Deforestation: Deforestation of land causes the soil to become loose and easily erodible. Thus, wind and rainwater cause soil erosion when the land is exposed after cutting down trees.

 

 

2. Unscientific methods of cultivation: Methods of shifting cultivation (e.g. Jhum) damage the soil and lead to high levels of erosion.

3. Overgrazing: Overgrazing of animals on the same fields remove the grass cover of the land. The soil is exposed to natural forces and becomes prone to erosion.

 

 

4. Population: The increasing population is a cause of soil erosion, an increase in population leads to an increase in the construction of roads, railways, houses, drainage lines, deforestation, increased agricultural activities, etc. All these lead to soil erosion.

5. Unscientific mining: Unscientific mining activities may damage the topmost layer of soil and cause erosion. If the excavated mines are not filled up properly, the roofs may collapse and cause disasters. Thus, unscientific mining increases the level of soil erosion.

6. Conventional method of farming: Traditional systems of agriculture may also cause soil erosion. Excessive application of chemical fertilisers and pesticides, and the use of tractors and harvesters tend to loosen the soil. Over-irrigation also makes the soil saline and infertile.

 

 

7. Landslide: Unauthorised construction, unplanned agriculture and deforestation tend to loosen the soil of mountain slopes and cause landslides. Falling of stones, pebbles, rocks and boulders along the hill slopes causes heavy soil erosion.

 

“WBBSE Class 10 Geography Chapter 5 Soil notes”

Question 2. Discuss the effects of soil erosion in India.
Answer:

The effects of soil erosion in India are as follows—

1. Decrease in the underground water level and soil humidity: The topsoil is generally more porous and softer than the lower layers. It helps in the absorption of rainwater and percolation in order to recharge the groundwater.

If this layer is removed, the relatively harder and less porous layer is exposed, which allows less percolation of the water. Thus, the level of underground waterfalls and the soil tends to dry up.

2. Removal of fertile topsoil: The essential minerals present in the topsoil are removed due to erosion. This reduces the fertility of the soil and hence reduces its productivity.

3. Deposition of silt in rivers and canals: The eroded soil particles are washed away by surface runoff and are deposited in rivers, lakes, canals, ponds and other water bodies. This reduces the depth of the water bodies. It may also lead to a flood.

4. Spreading of deserts: In arid and desert regions, the wind is the active agent of soil erosion. The wind blows away the topsoil and the sand particles from desert regions and drops them elsewhere.

This covers fertile lands with sand particles. Thus, the fertility of the land is reduced and the desert is extended. E.g. The area of the Thar desert is increasing in this way.

5. Floods and droughts: The deposition of eroded soil in rivers, lakes and other water bodies reduces their depth and cause floods in the rainy season.

On the other hand, erosion of the fertile and fine textured topsoil exposes the granular lower layers, which have less water-holding capacities. The Spread of sand particles makes fertile lands infertile and unproductive, which may result in droughts.

6. Landslides: Deforestation or unscientific construction in hilly regions loosens the soil, which easily falls off along the slopes due to gravitational forces. Thus landslides occur frequently, which increase soil erosion.

7. Hindrance in economic and cultural development: Soil erosion hampers agricultural production and affects the economy. Life of people becomes more and more difficult in regions which are severely prone to erosion, e.g. deserts, hilly regions, and flood-prone regions.

The Spread of deserts and the reduction of the productivity of land hampers the cultural development of that place.

Question 3. Discuss the characteristics of the soils of India along with their distribution.
Answer:

The main types of soil found in India are—

1. Alluvial soil
2. Black or regur soil
3. Red soil
4. Laterite soil
5. Desert soil
6. Mountain soil.

The characteristics and distribution of the different types of soils in India are as follows—

Soil	Distribution	Characteristic features
1. Alluvial soil of river basins	River basins and deltas of rivers Indus, Ganga, Brahmaputra, etc.	1. Alluvium is deposited when the river floods its basin areas. 2.  Presence of silt makes the soil very fertile. 3. The soil is rich in potash and calcium compounds. 4.  The soil is suitable for growing rice, wheat, jowar, bajra, pulses, oilseeds, cotton, sugarcane, jute and vegetables.
2. Alluvial soil of coastal regions	Eastern and Western Coastal Plains, delta regions, Sundarban region of West Bengal.	1.  Formed mainly due to the deposition of oceanic silt. 2.  Presence of sand and salts make the soil moderately fertile. 3.  Suitable for growing coconut and betelnut. 4.  Mangrove forests grow in the saline soil of lowlands in deltas.
Black soil	Deccan trap region of northwestern Deccan plateau, the plateau of Maharashtra, Bharuch, Vadodara, and Surat of Gujarat, Western Madhya Pradesh, northern Karnataka.	1.  Formed by weathering of basalt. 2. The soil is black in colour. 3. The soil has a high percentage of clay particles, hence water holding capacity is high. 4.  Suitable for growing cotton. Hence, also known as black cotton soil. 5. The soil is very fertile. 6. Other crops grown are—food grains, oilseeds, citrus fruits, vegetables, etc.
Red soil	Tamil Nadu, Karnataka and Andhra Pradesh of Deccan plateau, plateau of Maharashtra, Chotanagpur plateau of Jharkhand, hilly region north-eastern India, plateau of Meghalaya.	1. Formed by weathering of igneous and metamorphic rocks like granite and gneiss. 2.  Presence of ferric oxides in the soil makes it red in colour. 3. Water holding capacity low. 4.  Rich in potash and phosphate minerals. 5.  Suitable for growing ragi, rice, tobacco, groundnuts, potatoes, vegetables, etc.
Laterite soil	Western Ghats, Nilgiri hills, hilly region of Odisha, Chotanagpur plateau of Jharkhand	1.  Rich is oxides of iron and aluminium. 2. The soil is reddish in colour and hard like brick. 3.  The soil lacks nitrogen, phosphoric acid, potash, lime and magnesium. 4. The soil is less fertile. 5. Crops like rice, sugarcane and ragi are grown with the help of irrigation.
Desert soil	Desert region of Rajasthan, Kachchh and Kathiawar region of Gujarat.	Characteristic features 1. The soil is sandy, rich in salts and lacks organic matter.2. The soil is rich in phosphates but lacks nitrogen.3. Crops grown (with the help of irrigation) are—jowar, bajra, wheat and cotton.
Mountain soil	Western and eastern Himalayas, Western Ghats, Eastern Ghats, Cardamom hills.	1. The soil is not deep due to the steep slope of the mountainous regions and has a young immature profile. 2.  The soil lacks potash, phosphorus and lime, but is rich in organic matter. 3.  Podzol soil is found on the higher slopes of the mountains and chestnut soil is found on the lower slopes of the mountains. 4. Crops grown are—rubber, tea, coffee, spices, fruits, etc.

 

 

“Types of soils in India Class 10”

Question 4. How can soil erosion be recorded and soil be conserved?
Answer:

Prevention of erosion and conservation of soil is very important in order to retain the fertility and quality of the soil.

The steps that can be taken for the conservation of soil are as follows—

1. Afforestation: The roots of plants help to hold the soil tightly and the canopy of leaves overhead help to prevent the rainwater from splashing directly on the soil. These help to prevent soil erosion. Thus, barren and open lands must be afforested in order to conserve the soil.

2. Contour Farming: In hilly regions, agriculture can be done by the method of contour farming. This helps to break the slope of the land by cutting down the slopes into flattened stretches or steps so that the speed of running water can be reduced. This in turn helps to reduce soil erosion.

 

 

3. Gully Farming: In regions where gully erosion is predominant due to heavy rainfall, cultivation is done in narrow strips across the direction of the flow of water. This reduces the speed of flowing water as well as reduces the level of erosion.

4. Prevention of Jhum Cultivation: In jhum cultivation and other methods of shifting cultivation, forested land is cleared for agriculture. After three or four years, this land is discarded when fertility reduces and affects crop production.

Once again another stretch of forested land is cleared and cultivated in the same way. This process is very harmful for the environment as biomass is destroyed considerably and soil is exposed to erosion. Therefore soil can be conserved if jhum cultivation or other shifting cultivation is prevented.

5. Step Farming: The hill slopes are cut into steps or stairs for practising agriculture. The flat lands thus formed help in holding the running water. This helps in agriculture as well as reduces soil erosion.

 

 

6. Strip Farming: In hilly regions with steep slopes, agriculture can be practised in narrow strips of land across the direction of the slope. This helps to hold the soil tightly and reduces erosion. Erosion-preventive crops like pulses, soybean, nuts, etc. can be grown. The vegetative cover helps to hold the rainwater and increases the humidity of the soil.

Chapter 5 India-Physical Environment Topic 5 Soils In India Short Explanatory Answer Type Questions

Question 1. What do you understand by ‘Khadar and Bahangar’?
Answer:

Khadar and Bahangar

Two types of alluvial soil are found in the Gangetic Plains of northern India. These are— khadar and bhangar.

1. Khadar:

1. The new alluvial soil found on the banks of the rivers is called Khadar.
2. Khadar is very fertile as the alluvium brought down by the rivers is renewed every year.
3. The soil is loamy and porous.
4. The soil is light brown in colour.

2. Bhangar:

1. The old alluvial soil is known as a hangar.
2. This lies higher up in the flood plains, on the river terraces at a distance from the rivers.
3.  This soil is rich in calcium carbonate.
4. The soil is clayey and non-porous.
5. This soil is dark in colour and is less fertile than the new alluvium.

Question 2. Write a short note on laterite soil.
Answer:

Laterite soil

The word ‘laterite’ comes from the Latin word ‘later’, meaning ‘brick’.

Laterite soil regions in India: In India, laterite soil is found in the high temperature and heavy rainfall regions of the Western Ghats, Nilgiri hills and Cardamom hills of the Peninsular plateau, Hilly regions of Odisha, the Chotanagpur plateau of Jharkhand, etc.

Characteristic features:

1. Due to heavy rainfall, the salts and other soluble minerals are washed down into the bottom layers from the surface of the soil.
2. The soil texture is coarse with big air spaces in between. Hence, it has very less water holding capacity.
3. This soil is less fertile and not very suitable for agriculture.
4. The upper layers of laterite soil become very hard like bricks when dry.
5. The soil is reddish or brownish in colour.

Question 3. Mention the characteristic features of black soil. OR, Where is black soil found in India? Discuss its characteristics. OR, Write a short note on the black soil of India.

Answer:

Black soil regions in India:

1. Maximum availability of black soil is seen in the Deccan Trap region of Maharastra in the northwestern part of the Deccan plateau.
2. Black soil is also found in Bharuch, Vadodara and Surat of Gujarat, western parts of Madhya Pradesh and northern parts of Karnataka.

Characteristic features:

1. Black soil is formed by the weathering of basalt.
2. This soil is also called Regur, derived from the Telegu word ‘Regada’.
3. The soil is rich in iron oxides. The blackish colour comes from black crystalline schists and basic gneisses.
4. The soil is fine textured with a high amount of clay and silt present in the soil.
5. Although the soil is deficient in nitrogen, the calcium, potassium, lime, aluminium and magnesium carbonate present in the soil make it very fertile.
6. The water-holding capacity of black soil is high.
7. Cotton grows best in this soil. Thus, the soil is also known as black cotton soil.
8. Other crops growing well in this soil are—sugarcane (Vidarbha, Marathwada), groundnuts (northern Karnataka), jowar, oranges (Nagpur), onion (Nasik), etc.

“Soil formation process in India WBBSE”

Question 4. What are the effects of regur soil on agriculture?
Answer:

The effects of regur soil on agriculture

The black soil is also known as ‘regur’, the term derived from the Telegu word ‘Regada’. The soil is formed due to weathering of basalt of the Deccan plateau region. The soil is rich in iron, lime, magnesium, potassium and aluminium,
which makes it very fertile. However, it is poor in phosphates, nitrogen and organic matter.

The high water holding capacity due to fine soil particles is another important factor for the high fertility of the soil. Cotton grows best in black soil. Hence, the soil is also known as black, cotton soil. Other crops grown in this soil are sugarcane, groundnuts, tobacco, onion, orange, etc. The black soil or regur soil regions are one of the best agricultural regions in India.

Question 5. Write a short note on the red soil region of India.
Answer:

The red soil region of India

Red soil regions in India: Red soil is found in India in the states of Andhra Pradesh, Karnataka and Tamil Nadu, the plateau region of Maharashtra, the Chotanagpur plateau of Jharkhand, hilly regions of northeastern India and the Meghalaya plateau.

Characteristic features:

1. Red soil is formed from the weathering of igneous and metamorphic rocks like granite and gneiss.
2. High amounts of ferric compounds make the soil appear red in colour.
3. The water-holding capacity of red soil is very low
4. The soil is rich in potash.
5. The crops grown in this soil are— ragi, rice, tobacco, groundnuts, pulses and vegetables.

Question 6. Name three important soil regions of India.
Answer:

The three important soil regions of India, according to the level of fertility and productivity

soil region	Geographical area
1. Alluvial	The Indus-Ganga-Brahmaputra plains of northern India, the delta region of the Ganga, and the coastal regions on the eastern and western margins of India.
2. Black soil region	Plateau region of Maharashtra, the south-eastern part of Gujarat, the southern part of Madhya Pradesh, the northern part of Karnataka, etc.
3. Red soil region	The plateau regions of Tamil Nadu, Karnataka, Andhra Pradesh, Odisha, etc.

 

Question 7. What is the alluvial soil of the river basins known in different parts of India?
Answer:

Alluvial soil is known by different names in different parts of India. They are as follows—

Name of alluvial soil	Geographical location
1. Bhangar	Old alluvium deposits on the river terraces.
2. Khadar	Newer alluvium deposits on the river banks.
3. Bet	Sutlej plains in Punjab.
4. Bhabar	Lies along the foothills of the Shiwalikhs formed due to the merging of alluvial fans.
5. Reh/Usar/ Kallar	Saline and alkaline soils of the drier areas of Haryana.
6. Terai	Lies to the south of the baby belt. Mostly found in the eastern parts than in the western parts.
7. Karewa	Alluvial soil formed from deposits brought down by the glaciers in Kashmir valley.
8. Loess	Found in Madhya Pradesh.

 

“Importance of soil resources in India Class 10”

Question 8. Differentiate between red soil and laterite soil.
Answer:

The differences between red soil and laterite soil are as follows—

Point of difference	Red soil	Laterite soil
Formation	Formed due to weathering of old granite and gneiss rocks.	Formed by the accumulation of oxides of iron and aluminium on the surface while the other soluble minerals get washed down to the lower layers during heavy rain.
Location	Tamil Nadu, Karnataka, Andhra Pradesh, plateau regions of Maharashtra, Chotanagpur plateau of Jharkhand, hilly region of north-eastern India, plateau region of Meghalaya.	Western Ghats, Nilgiri and Cardamom hills, hilly region of Odisha, Chotanagpur plateau of Jharkhand.
Crops grown	Rice, wheat, jowar, bajra, etc. (with the help of irrigation)	Maize, jowar, bajra, coffee, cashew nuts, etc.

 

Question 9. Differentiate between Khadar and bhangra soil.
Answer:

The differences between Khadar and bhangra soil are as follows—

Point of difference	Khadar	Bangor
Location	On the flood plains on either side of the river, lying close to the banks.	On the river terraces on either side of the river a little far away from the banks.
Kankar deposits	Calcareous concentrations or kankar are not found.	Calcareous concentrations or kankar are found.
Fertility	This is very fertile as alluvium deposits are renewed every year due to the flooding of river banks.	This is less fertile as alluvium deposits are not renewed every year. Renewal of alluvium may occur only if the flood water spreads for a long distance from the river banks.

 

Question 10. Differentiate between alluvial soil.
Answer:

The differences between alluvial soil and black soil are as follows—

Point of difference	Alluvial soil	Black soil
Formation	Formed by deposition of silt, sand, clay brought by rivers and organic materials.
Colour	Varies from light brown to dark grey.	Varies from black to dark brown.
Location	Found in the river valleys of India, especially along the middle and lower courses	Found in the plateau region of Maharastra, parts of Gujarat and Madhya Pradesh, parts of Andhra Pradesh, Karnataka and Tamil Nadu
Crops grown	Rice, wheat, sugarcane, jute, etc	Cotton, tobacco, Wheat etc.

 

Question 11. Where is jhum cultivation practised in India, and how?
Answer:

Jhum is a kind of shifting cultivation practised in India mostly by the tribal and native people. The areas where jhum cultivation can be seen in India are—the north-eastern states of India, especially in Arunachal Pradesh, Mizoram, Tripura, Meghalaya and Nagaland.

Method of Jhum Cultivation: In jhum cultivation, first a portion of a forest on the hill slopes are chosen and burnt. The ash thus produced is mixed with soil and used as a fertiliser.

Then the seeds of various crops are sown in the soil. The soil can produce sufficient crops for three to four years, after which the fertility starts decreasing.

Hence, a new portion of the forest is chosen and burnt and cultivated in the same way. Jhum cultivation results in the massive destruction of forests and biomass and causes the destruction of ecosystems. This in turn results in environmental degradation.

“Characteristics of black soil in India WBBSE”

Question 12. Mention the causes of soil erosion in India and their possible solutions.
Answer:

Soil erosion refers to the removal of the topmost layer of soil by various natural agents like wind, rainfall, rivers, etc. and man-made causes like deforestation, unscientific cultivation, overgrazing, etc.

Solution: Soil erosion can be prevented or controlled by the following actions—

1. Afforestation or planting more trees.
2. Prevention of shifting cultivation, e.g. Jhum.
3. Controlled grazing of animals.
4. Scientific and planned methods of agriculture.

Question 13. How do unscientific mining landslides and deforestation cause soil erosion?
Answer:

Unscientific Mining: Mineral resources and ores of various kinds are excavated from mines by unscientific methods. This leaves the land exposed and prone to erosion. It may also lead to landslides if the mines are not filled up properly after excavation.

Landslides: The sudden fall of rocks and soil along the slope or topography due to man-made or natural reasons are known as landslides. The main causes of landslides are the construction of roadways and railways in hilly regions, the construction of dams and reservoirs on rivers, unscientific cultivation along hill slopes, etc.

Heavy rainfall, earthquakes, and unscientific construction of buildings in hilly regions increase the frequency and intensity of landslides.

Deforestation: The roots of the trees help to hold the soil tightly and prevent erosion. Cutting down trees loosens this bond and the exposed soil becomes easily erodible by wind and surface runoff coming from rainfall.

Question 14. Describe the regions facing problems of soil erosion in India.
Answer:

Soil erosion is a common problem faced in India.

The various regions of India facing soil erosion are—

1. Himalayan region, Western Ghats and Eastern Ghats due to erosion by running water.
2. Rajasthan and Gujarat due to wind.
3. Himachal Pradesh, Jammu and Kashmir, parts of Rajasthan and Madhya Pradesh due to excessive grazing of animals on pastures.
4. Rajasthan, Uttar Pradesh and Punjab due to excessive deforestation.
5. Uttarakhand, Himachal Pradesh, Darjeeling, Sikkim and other hilly regions due to landslides.
6. North-eastern states of India and parts of Odisha due to shifting cultivation.

Question 15. Discuss the role of afforestation, step farming and strip farming in the prevention of soil erosion.
Answer:

Afforestation: The roots of the trees help to hold the soil tightly and the canopy of leaves overhead prevents the rainwater from directly falling on the soil. Both of this help to prevent soil erosion. Hence, open lands must be covered with vegetation to prevent the top layer of soil from being removed fast.

Step farming: The steep slope of the land in hilly regions increases the speed of soil erosion. If the slope is cut into steps or stairs, the general slope of the land can be reduced and flat stretches of land can be created along the hills. This helps to reduce the speed of running water, thus reducing soil erosion. Hence, step farming is an important method of preventing soil erosion.

Strip farming: Gullies are formed in regions where the soil is washed away by running water. Formation of gullies and washing away of soil can be reduced or prevented by planting fast-growing trees in strips across the direction of the flow of the running water. If the speed of the running water is reduced, its erosive capacity is also reduced.

“Soil erosion and conservation in India Class 10”

Question 16. How does the grazing of animals cause soil erosion?
Answer:

While grazing, the animals tend to pull out the roots of the grass and the small plants that they eat. This loosens up the topsoil. Also, the bonding of the soil is lost by the continuous stepping of the animals with hooves on the ground. As a result, the top layer of soil is easily removed by running water.

The process of formation of ravines is called ravine erosion. Such ravines are found in Garhbeta in Medinipur, West Bengal.

Question 17. How does jhum cultivation cause soil erosion?
Answer:

In jhum cultivation, the forests are burnt, which removes the vegetative cover and exposes the soil. This exposed soil is prone to erosion by the splashing of rainwater. Thus, jhum cultivation leads to soil erosion.

Question 18. How does flowing water cause soil erosion?
Answer:

The different types of soil erosion caused by running water are—

1. Sheet erosion: When rainwater splashes on the open ground, loosens the soil particles and washes them away like a sheet from the top, it is called sheet erosion.

2. Rill erosion: In sloping lands, the surface runoff creates thin and shallow channels on the ground while flowing downwards. These thin channels are called rills and the method of removal of soil by the water running through these rills is called rill erosion.

3. Cully erosion: When rill erosion continues for many years, the narrow channels become wider and deeper. These come to be known as gullies and the method of erosion is called gully erosion.

4. Ravine erosion: The rills and gullies that have very steep sides are known as ravines The process of formation of ravines is called ravine erosion. Such ravines are found in Garhbeta in Medinipur, West Bengal.

Question 19. How does landform or topography influence soil erosion?
Answer:

Soil erosion is higher in hilly regions and plateaus compared to plain lands. In plateaus and hills, the soil is not thick and deep due to the slope. Thus, they are easily washed away by rainwater. The slope of the land speeds up the process of erosion, and the gravitational force enhances it.

Question 20. How does an increase in population influence soil erosion?
Answer:

An increase in population leads to more construction of roadways, railways, houses, drainage systems, etc. All these lead to the cutting down of natural vegetation and exposure of soil. Thus, an increase in population leads to soil erosion.

Question 21. What is contour ploughing?
Answer:

Contour ploughing

A contour is an imaginary line that joins all places having the same height above mean sea level. In hilly regions, if the land is flattened by cutting down the slope into steps or stretches and cultivation is carried out on these steps along the contours, the method of cultivation is known as contour ploughing. This method of cultivation reduces soil erosion by reducing the speed of running water.

Question 22. How does the traditional method agriculture cause of soil erosion?
Answer:

In the traditional methods of agriculture, chemical fertilisers and pesticides are used to make the soil fertile, without even judging the requirement of a particular component.

Tractors and harvesters which are used in traditional methods tend to loosen the soil and cause erosion. An increase in soil erosion results in the destruction of soil fertility. Thus, the traditional method of agriculture causes soil erosion.

Question 23. Differentiate between step farming and stip farming.
Answer:

The differences between step farming and strip farming are—

Point of difference	Step forming	Strip forming
Concept	Cultivation of crops on steps or stairs cut along the slope of the hills.	Cultivation of crops in narrow strips of land across the direction of the slope.
Type of Land	The slope of the mountain is cut into a series of steps in order to reduce the slope and control soil erosion. Crops are grown on each step.	Agriculture is practised in strips of land on the hills across the direction of the slope in order to check soil erosion and landslide.
Crops grown	Here erosion resistant crops are not required to be grown. Crops like rice, wheat, maize, etc. are grown.	Here erosion resistant crops are required to be grown, e.g. groundnuts, soybean, etc.

Chapter 5 India-Physical Environment Topic 5 Soils In India

Short Answer Type Questions

Question 1. What is soil?
Answer:

Soil:

Soil is the thin layer present on the surface of the earth composed of disintegrated rocks and decayed organic matter. It sustains the vegetation cover and stores groundwater for the use of both plants and humans.

The minerals present in the parent rocks, the texture of the grains, the structure of the soil, the porosity and the humus content decide the level of fertility of the soil. E.g. Alluvial soil, laterite soil, red soil, etc.

Question 2. Name the major types of soils found in India.
Answer:

Different types of soils are found in different parts of India due to differences in the type of parent rocks, topography vegetative cover and climatic conditions.

The major types of soils found in India are—

1. Alluvial soil
2. Black or Regur soil
3. Red soil
4. Laterite soil
5. Desert soil
6. Mountain soil.

Question 3. Which soils of India are important for agriculture?
Answer:

Agriculture is dependent on the type of soil found in a region.

The soils that are the most suited for agriculture in India are—

1. Alluvial soil
2. Black or regur soil
3. Red soil.

Question 4. Classify alluvial soil according to texture.
Answer:

Alluvial soil can be classified into three types according to the ratio of silt, sand and clay present in the soil.

They are—

1. Sandy soil (percentage of sand is high)
2. Loamy soil (percentage of sand, silt and clay is almost equal)
3. Clayey soil (percentage of clay is high).

Question 5. Name some crops grown in alluvial soil.
Answer:

Some crops grown in alluvial soil are—rice, wheat, jute, cotton, sugarcane, etc.

Question 6. What is podzol soil?
Answer:

Podzol soil

The acidic soil rich in humus, found in the coniferous forest regions on the mountain slopes is known as podzol soil. Example—In India, podzol soil is found in the mountainous region of Himachal Pradesh and Jammu and Kashmir, where coniferous forests have grown.

“Soil fertility factors in India Class 10 Geography”

Question 7. Name some regions where black soil is found in India.
Answer:

In India, black soil is found in the plateau regions of Maharashtra, Bharuch, Vadodara and Surat in Gujarat, the western region of Madhya Pradesh, and the northern region of Karnataka.

Question 8. In which regions of India saline soil is found?
Answer:

In India, saline soil is found in the coastal regions. Example—Sundarbans. It is also found in the arid and semi-arid regions of Rajasthan, Haryana, Uttar Pradesh and Bihar.

Question 9. Where is laterite soil found in India?
Answer:

Laterite soil is found in India in the Western Ghats, Nilgiri hills and Cardamom hills of the Deccan plateau, hilly region of Odisha and Chotanagpur plateau.

Question 10. What are ‘Bhur’ and ‘Regur’?
Answer:

‘Bhur’ and ‘Regur’

‘Bhur’: Bhur is the slightly undulating highlands made up of very fine soil, lying in the upper doab region of the Ganga plains in western Uttar Pradesh. These plains are less fertile.

‘Regur’: The black-coloured soil formed due to the weathering of basalt rocks in the Deccan plateau region is called regur. The term regur comes from the Telegu word ‘Regada’. This is very fertile soil and best suited for the cultivation of cotton.

Question 11. What is ‘Khadar’?
Answer:

Khadar

The new alluvial soil found in the flood plains of the Ganga in northern India, is known as ‘Khadar’. The fertility of khadar is more than bhangra as the soil is replenished by the layer of fresh deposits of alluvium every year.

Question 12. Why has black soil been formed in the Deccan Trap region?
Answer:

The Deccan Trap is a region in the northwestern part of the Deccan plateau formed of lava deposits. The rocks found in this region are of volcanic origin. E.g.—Basalt. The black soil has formed due to the weathering of this basalt.

Question 13. Why is alluvial soil very fertile?
Answer:

The alluvial soil is rich in plant nutrients such as potash and potassium. The ratio of sand, clay and loam present in the soil is almost equal. All these factors make the soil very fertile and most suited for agriculture.

Question 14. Why does the regur soil appear black in colour?
Answer:

Regur soil is formed from the weathering of the basalt that makes up the surface of the Deccan plateau region. The black colour of the parent rock makes the regur soil black in colour. The black colour is also due to the presence of black crystalline schists and black gneisses.

Question 15. Why does the laterite soil appear red in colour?
Answer:

In regions receiving heavy rainfall, the soluble minerals present in the soil, e.g.— potassium, calcium and magnesium are washed downwards from the surface into the lower layers by rainwater.

The iron and aluminium oxides remain in the upper layers of the soil. Thus, laterite soil present in these regions appears red in colour.

Question 16. Why is black soil or regur soil of India so fertile?
Answer:

Although the black soil or regur soil lacks nitrogen, phosphate and organic matter, it is rich in calcium, lime, magnesium, potassium, etc.

Besides this, it is also rich in clay and silt particles, which increases its water-holding capacity. Thus, all these factors make the black soil or regur soil of India very fertile.

Question 17. Why is the laterite soil called so?
Answer:

The word ‘laterite’ comes from the Latin word ‘later’ meaning brick. As the soil appears to be reddish like the colour of a brick, it is called laterite soil.

Question 18. Name some crops grown in black soil.
Answer:

Some crops grown in black soil are—cotton, groundnut, wheat, onion, oilseeds, tobacco, etc.

Question 19. Name some crops grown in red soil.
Answer:

Some crops grown in this soil are—maize, soya bean, groundnuts, coffee, millet, grapes, etc.

Question 20. Mention two characteristics of soil found in the coastal areas.
Answer:

The two characteristics of the soil found in coastal areas are—

1. The soil found in coastal regions is saline due to the influence of the sea.
2. The presence of sand particles in coastal soils is high. But in regions where the rivers meet the sea, the soil is more clayey than sandy.

Question 21. Which crops grow well in mountain soil?
Answer:

Mountain soil is suitable for various plantation crops. The crops grown in this soil are—tea, coffee, spices, wheat, barley, etc. Fruits like apples, oranges, cherries and different kinds of berries are grown in orchards in mountainous regions.

Question 22. Name some crops grown in desert soil.
Answer:

Some crops grown in desert soil

Desert soil is very dry and not suitable for agriculture. If irrigation facilities are provided, some crops like cotton, wheat, barley, pulses and millets can be grown in desert soil.

Question 23. Mention some methods of reducing or controlling soil erosion.
Answer:

The methods by which soil erosion can be reduced or controlled are—

1. Planting trees or afforestation.
2. Scientific methods of agriculture.
3. Prevention of jhum and other methods of shifting cultivation.
4. Controlled grazing of animals.
5. Contour farming and step farming along the mountain slopes in hilly regions.
6. Covering open lands with vegetation covers.
7. Crop rotation, etc.

Question 24. What are the various causes of soil erosion?
Answer:

The various causes of soil erosion are—

Natural causes:

1. Storms and strong winds
2. Rainfall,
3. Rivers, etc.

Man-made causes:

1. Deforestation,
2. Unscientific agricultural practices,
3. Overgrazing of animals, etc.

Question 25. What do you understand by soil erosion?
Answer:

Soil erosion

The removal of the topmost layer of soil by natural forces (e.g., wind, river, rainfall, etc.) or man-made causes (e.g., deforestation, unscientific agriculture, overgrazing, etc.) is known as soil erosion. Erosion of the top layer of soil reduces the fertility of the soil considerably.

Question 26. Which regions of India are prone to soil erosion?
Answer:

The regions of India that are prone to soil erosion are—Meghalaya, Nagaland and Manipur of north-eastern India, Chotanagpur plateau of Jharkhand, Eastern Ghats, Western Ghats, the desert in Rajasthan, parts of Punjab, Gujarat, Madhya Pradesh, etc.

Chapter 5 India Physical Environment Topic 5 Soils In India Multiple Choice Type Questions

Write The Correct Answer From The Given Alternatives

Question 1. The old alluvium soil of the Northern Plains of India is called—

1. Bhangar
2. Khadar
3. Terai
4. Bhur

Answer: 1. Bhangar

Question 2. The most important soil for agriculture in India is—

1. Alluvial soil
2. Red soil
3. Black soil
4. Sandy soil

Answer: 1. Alluvial soil

Question 3. ‘Bhur’ is found in—

1. Desert
2. Plateau
3. Gangetic Plains
4. Deccan region

Answer: 3. Gangetic Plains

Question 4. Laterite soil is found in—

1. Desert of Rajasthan
2. Chotanagpur plateau
3. Gangetic Plains
4. Himalayan mountains

Answer: Chotanagpur plateau

Question 5. Podzol soil is found in—

1. Coniferous forest region
2. Plateau region
3. Plains
4. Desert regions

Answer: Coniferous forest region

Question 6. Weathering of granite and gneiss give rise to—

1. Laterite soil
2. Black soil
3. Red soil
4. Alluvial soil

Answer: 3. Red soil

Question 7. Soil is found at the mouth of the rivers—

1. Alluvial soil
2. Mountain soil
3. Saline alluvial soil
4. Red soil

Answer: 3. Saline alluvial soil

Question 8. Meghalaya plateau is mostly composed of—

1. Laterite soil
2. Alluvial soil
3. Desert soil
4. Black soil

Answer: 1. Laterite soil

Question 9. The new alluvial soil of the Gangetic plains is known as—

1. Bhabar
2. Khadar
3. Terai
4. Bhangar

Answer: Bhangar

Question 10. The water holding capacity of black soil is—

1. Very high
2. Very low
3. Medium
4. Low

Answer: 1. Very high

Question 11. The soil mixed with sand, pebbles, gravel and silt found in the foothill regions of the Himalayas is called—

1. Bhangar
2. Khadar
3. Terai
4. Bhabar

Answer: Bhangar

Question 12. Sandy soil is good for cultivating—

1. Cucumber
2. Rice
3. Wheat
4. Tea

Answer: 1. Cucumber

Question 13. Water holding capacity of laterite soil is less because it is—

1. Sandy
2. Gravelly
3. Clayey
4. Highly porous

Answer: 2. Gravelly

Question 14. Mountain soil is—

1. Acidic
2. Alkaline
3. Saline
4. Highly alkaline

Answer: 1. Acidic

Question 15. The soil found in the desert region of Rajasthan is called—

1. Alluvial soil
2. Red soil
3. Desert soil
4. Laterite soil

Answer: 3. Desert soil

Question 16. The desert soil is—

1. Alkaline
2. Acidic
3. Neutral pH
4. None of these

Answer: 1. Alkaline

Question 17. In West Bengal, laterite soil is found in the district of—

1. Darjeeling
2. Nadia
3. Purulia
4. Howrah

Answer: 3. Purulia

Question 18. Desert soil is good for growing—

1. Millets
2. Rice
3. Wheat
4. Oilseeds

Answer: 1. Millets

Question 19. The soil research centre of India is located in—

1. Kolkata
2. Jaipur
3. Kochi
4. Dehradun

Answer: 2. Jaipur

Question 20. The main cause of gully erosion is—

1. Surface runoff
2. Wind
3. Ocean currents
4. Agriculture

Answer: 1. Surface runoff

Question 21. A man-made cause of soil erosion in India is—

1. Weathering
2. Erosion by surface runoff
3. Unscientific agricultural practices
4. Wind

Answer: 3. Unscientific agricultural practices

Question 22. The practice of agriculture in hilly regions by cutting the slopes into thin stretches of flat land is called—

1. Gully cultivation
2. Strip cultivation
3. Afforestation
4. Step cultivation

Answer: 3. Afforestation

Question 23. Soil conservation in hilly regions can be done by the process of—

1. Planting trees
2. Step cultivation
3. Constructing roads
4. Constructing dams across rivers

Answer: 2. Step cultivation

Question 24. The method of soil erosion by layers due to surface runoff created by rainfall is called—

1. Rill erosion
2. Valley erosion
3. Gully erosion
4. Sheet erosion

Answer: 4. Sheet erosion

Question 25. Soil erosion increases due to—

1. Shifting cultivation
2. Step cultivation
3. Contour farming
4. Strip farming

Answer: 1. Shifting cultivation

Question 26. The laterite soil is found in the region of—

1. Ganga plain
2. The western slope of western ghat
3. Sundarban
4. Desert region

Answer: 2. Western slope of western ghat

 

Chapter 5 India Physical Environment Topic 5 Soils In India If The Statement Is True

Write True And If False Write False Against The Following

Question 1. The new soil of the river valleys is called regur.
Answer: False

Question 2. Cotton grows best in laterite soil.
Answer: False

Question 3. The presence of ferric oxide makes the soil red in colour.
Answer: True

Question 4. Desert and semi-desert regions have sandy soil.
Answer: True

Question 5. Red soil is commonly found in the Thar desert.
Answer: False

Question 6. Laterite soil is reddish or brownish in colour.
Answer: True

Question 7. Desert soil is acidic in nature.
Answer: False

Question 8. Laterite soil is found in the Gangetic Plains.
Answer: False

Question 9. Cotton is grown in saline soil.
Answer: False

Question 10. Desert soil is also known as podzol soil.
Answer: False

Question 11. Mountain soil comprises very thin layers.
Answer: True

Question 12. Black soil needs a lot of fertilisers for agriculture.
Answer: False

Question 13. The red soil has a low water-holding capacity.
Answer: True

Question 14. Black soil contains high percentages of silt and clay.
Answer: True

Question 15. The laterite soil becomes very hard when dry.
Answer: True

Question 16. ‘JhunV is a type of shifting cultivation.
Answer: True

Question 17. Soil erosion can be prevented by afforestation.
Answer: True

Question 18. Jhum cultivation helps to increase soil fertility.
Answer: False

Question 19. Gullies are created in lateritic soil regions due to sheet erosion.
Answer: False

Question 20. The wind is an agent of soil erosion.
Answer: True

Question 21. Soil erosion occurs at the same level all over India.
Answer: False

Question 22. Excessive irrigation makes soil saline.
Answer: True

Question 23. Crop rotation does not help in increasing soil fertility.
Answer: False

Question 24. Step cultivation helps to reduce soil erosion in hilly regions.
Answer: True

Question 25. Strip cultivation increases soil erosion.
Answer: False

Chapter 5 Indian-Physical Environment Topic 5 Soils In India Fill In The Blanks With Suitable Words

Question 1. ______soil is found in the Northern Plains of India.
Answer: Alluvial

Question 2. Desert soil lacks ______ content.
Answer: Humus

Question 3. ______ soil is famous for cotton cultivation.
Answer: Black/regur

Question 4. The new alluvial soil of northern India is called ______
Answer: khadar

Question 5. The Indian Council of Agricultural Research (ICAR) classifies Indian soil into ______ types.
Answer: Eight

Question 6. ______ crops are grown in desert soil.
Answer: Millet

Question 7. Mountain soil is ______ in colour.
Answer: Grey

Question 8. Bhangar soil has high concentrations of calcium carbonate (lime) called ______
Answer: Kankar

Question 9. The soil of coastal regions is ______ in nature.
Answer: Sailine

Question 10. Alluvial soil is ______ in humus and nitrogen.
Answer: Deficient

Question 11. Black soil is formed due to weathering of ______
Answer: Basalt

Question 12. Weathering of granite and gneiss rocks forms ______ soil.
Answer: Red

Question 13. The red soil appears red due to the presence of ______
Answer: Ferric oxide

Question 14. Laterite soil is rich in iron and ______
Answer: Aluminum oxide

Question 15. ______ soil is found in the Bankura and Birbhum districts of West Bengal.
Answer: Red

Question 16. Desert soil has a very low water-holding ______ capacity as it is highly
Answer: Porous

Question 17. Mountain soil is rich in ______
Answer: Humus

Question 18. The Deccan plateau is covered with ______ soil.
Answer: Black/Regular

Question 19. The soil of the Sundarban region is ______ in nature.
Answer: Saline

Question 20. The soils of mountain regions are ______ than the soils of plains.
Answer: Immature

Question 21. Soil erosion not only refers to the removal of the top layer of soil but also the decrease of______
Answer: Fertility

Question 22. Rill erosion is a form of______ erosion.
Answer: Gully

Question 23. One of the man-made causes of soil erosion is ______
Answer: Deforestation

Question 24. Jhum cultivation is practised in the hilly region of______ India.
Answer: Northeastern

Chapter 5 Indian-Physical Environment Topic 5 Soils In India

Answer In One Or Two Words

Question 1. Name two states of India where laterite soil is found.
Answer: Meghalaya, Assam.

Question 2. In which soil does tea grow well?
Answer: Mountain soil.

Question 3. Which soil is deficient in humus, but is rich in potash, iron, calcium, and aluminium?
Answer: Black soil or regur.

Question 4. Which soil contains the least amount of hummus?
Answer: Desert soil.

Question 5. Which soil is best suited for cultivating rice?
Answer: Alluvial soil.

Question 6. Name the source of the word ‘regur’.
Answer: Telegu word ‘Regada’.

Question 7. What is alluvial soil known as in Kashmir Valley?
Answer: Karewa.

Question 8. Which kind of soil has a pH value of less than 7?
Answer: Acidic soils.

Question 9. Which is the most fertile soil in India?
Answer: Alluvial soil.

Question 10. Which soil has an equal ratio of clay and sand?
Answer: Loamy soil.

Question 11. Which soil has high contents of sand?
Answer: Sandy soil.

Question12. Where is loess soil found in India?
Answer: Madhya Pradesh.

Question 13. Which soil becomes very hard when dry?
Answer: Laterite soil.

Question 14. What is the hard layer formed at the top of laterite soil called?
Answer: Duricrust.

Question 15. What are the deposits of new alluvium in the river basins of Punjab known as?
Answer: Bet.

Question 16. Which minerals are present in high amounts in pedalfer soils?
Answer: Aluminium and iron.

Question 17. What is the sandy soil of the desert region known as?
Answer: Sierozem.

Question 18. Which mineral is present in high amounts in the pedal soils?
Answer: Calcium carbonate.

Question 19. What is the main cause of soil erosion in Rajasthan?
Answer: Wind.

Question 20. How can soil be conserved in regions of gully erosion?
Answer: Cultivation or planting trees along the gullies.

Question 21. Name a method of cultivation practised in hilly regions to prevent soil erosion.
Answer: Contour farming.

Question 22. Where is Jhum cultivation seen in India?
Answer: North-eastern India.

Question 23. Mention two natural causes of soil erosion.
Answer: Wind and surface runoff (rainwater).

Question 24. Mention two man-made causes of soil erosion.
Answer: Deforestation and traditional or primitive methods of cultivation

Chapter 5 Indian-Physical Environment Topic 5 Soils In India

Match The Left Column With The Right Column

1.

Left Column	Right Column
1.  Pedalfer	A.  Chernozem
2.  Pedocal	B.  Mountain soil
3.  Rendzina	C.  Podzol
4. Slerozem	D.  Black soil
5.  Regur	E. Desert soil

 

Answer: 1-C,2-A,3-B,4-E,5-D

2.

Left Column	Right Column
1.  Alluvial soil	A. Comes from basalt
2.  Black soil	B. Good for agriculture
3.  Red soil	C.  Comes from granite
4.  New alluvium	D.  Kashmir valley
5.  Karewa	E.  Khadar

 

Answer: 1-B,2-A,3-C,4e,5-D

3.

Left Column	Right Column
1.  Jhum cultivation	A. Preventing soil erosion
2.  Step cultivation	B. North-east India
3. Desertification	C.  Rainwater
4. Sheet erosion	D. Mountain Slope
5.  Landslide	E.  Increases slope erosion

 

Answer: 1-B,2-A,3-E,4-C,5-D