WBBSE Solutions For Class 8 Geography Chapter 4 Pressure Belts And Wind Movement Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Analytical Type Questions

Question 1. Explain briefly the relation between the pressure belts and the planetary winds.
Answer:

Relation Between The Pressure Belts And The Planetary Winds:-

There are seven pressure belts around the world which are very closely related to the planetary winds. As the earth rotates from west to east, the winds get deflected to the right in the northern hemisphere and to the left in the southern hemisphere.

Winds blow from high-pressure zones to low-pressure zones to maintain a balance between the air pressure of different regions. There are four high-pressure and three low-pressure belts on the earth.

Permanent or planetary winds arise from sub-tropical and polar high-pressure belts and move towards equatorial and sub-polar low-pressure belts. There are three planetary winds, namely-trade winds, westerlies and polar winds.

Trade winds:

The permanent low-pressure belt of the equatorial region attracts winds from the sub-tropical high-pressure belts. This wind blows from the northeast in the northern hemisphere and from south-east in the southern hemisphere (by Ferrel’s law) and are called north-east trade winds and southeast trade winds respectively.

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As per nautical expression the term ‘trade’ suggests blowing along a regular path. Trade winds shift more to the north and south of their normal paths following the annual migration of the sun.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Wind Movement on the earth

 

Westerlies:

These blow outside the tropics, in the temperate zone, mainly to the opposite direction of the trade winds between 35° and 60° north and south latitudes.

These also get deflected due to the rotational force of the earth and blow from the southwest in the northern hemisphere and from the northwest in the southern hemisphere.

As these are western winds, they cause rainfall chiefly in the western parts of the continents, keeping the eastern sides dry. These winds do not follow a fixed direction or path either.

However, in the southern hemisphere, the westerlies are much stronger due to the absence of larger landmasses which obstruct their path and reduce the wind speed in the northern hemisphere.

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Polar winds:

Scientists have established that there exist two permanent high-pressure belts in the south and north poles and two comparatively low-pressure belts along the sub-polar regions.

Due to this, icy polar winds blow from high-pressure zones of the poles to the sub-polar low-pressure zones regularly. These winds deflect towards the west in both hemispheres. These are called the polar easterlies.

Question 2. Classify the trade winds and discuss their characteristics and influence.
Answer:

Classification Of Trade Winds:-

The winds that blow from sub-tropical high-pressure belts of both the hemispheres to the equatorial low-pressure belt are called the trade winds. This is a permanent wind blowing regularly throughout the year in the same direction at a uniform speed.

There are two types of trade winds

North-east trade winds:

These winds blow from the sub-tropical high-pressure belt of the northern hemisphere towards the equatorial low-pressure belt. They deviate to the right and blow from the north-east direction according to Ferrel’s law. so these winds are known as the northeast trade winds.

South-east trade winds:

These winds blow from the sub-tropical high-pressure belt of  the southern hemisphere to the equatorial low-pressure belt and deviate to the left as per Ferrel’s law. They blow from southeast so these winds are known as the southeast trade winds.

Characteristics:

The characteristics of trade winds are

1. Velocity:

Having vast stretches of landmass in their path in the northern hemisphere, here the trade winds blow at a slower speed of nearly 16km/h. On the other hand, the southern hemisphere has less landmass compared to waterbodies.

So the winds travel here at a high velocity of 22-30km/h.

2. Extent:

The trade winds normally blow within 5°-25° north and south latitudes on either side of the equator.

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Influence:

The trade winds have contributed to the development of the hot deserts in the world. The deserts are situated on the western margins of the continents that are not benefited by the moisture brought in easterly trade winds.

As a result, deserts such as the Kalahari, the Sahara and the Atacama have developed. On the other hand, the trade winds are blessings to the farmers in the eastern parts of the continents, where these winds cause sufficient precipitation for cultivation of crops.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Wind Movement on the earth

 

Question 3. Classify and mention, the features Westerlies.
Answer:

Classification Of Westerlies:-

The westerlies are of two types

  1. In the northern hemisphere, as per the Ferrel’s law, the winds get deflected to the right while moving along their path towards the sub-polar low-pressure belt. So, they are known as the south-west westerlies in the northern hemisphere.
  2. Similarly, they become the north-west westerlies in the southern hemisphere due to the rotation of the earth.

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Features Of Westerlies:-

Some of the important features of the westerlies include

  1. The speed and direction of these winds are not as constant and steady as the trade winds.
  2. Having larger water- bodies along their way, the westerly winds collect sufficient water vapour to cause rainfall on the western margins of the continents.
  3. Apparent migration of the sun also shifts the area that comes under the influence of the westerlies slightly to the north or south of the equator.
  4. The southern hemisphere, having a larger percentage of water surface than landmass, records stronger and more constant westerly winds.
  5. The westerlies around 40°, 50° and 60° south latitudes, are called the ‘roaring forties’, ‘furious fifties’ and ‘screaming
    sixties’ respectively.
  6. The regions over which the westerlies blow, cyclones and anti-cyclones often originate.
  7. Westerlies are stronger in winter and weaker in summer.

Question 4. What do you know about the polar winds? Classify and explain their features.
Answer: The winds that blow from the high-pressure belts of the polar region to the sub-polar low pressure belts of both hemispheres, are called polar winds.

Classification Of Polar Winds:-

According to their path of flow, polar winds can be of two types

  1. Polarwinds that blow from the North Pole towards the sub-polar belt in the northern hemisphere, get deflected to the right (as per Ferrel’s law) and are called north-east polar winds.
  2. Similarly, winds blowing from the South pole towards the sub-polar belt in the southern hemisphere also get deflected to the left (as per Ferrel’s law) and are called south-east polar winds.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Polar winds

 

Features Of Polar Winds :-

Some important features of polar winds are

  1. The Polar winds are very cold and heavy.
  2. These are very dry and almost devoid of water vapour.
  3. These are more active in the southern hemisphere than in the northern hemisphere.
  4. Polar winds cause snowfall and blizzards at the poles.

Question 5. What are the effects of the planetary winds on earth?
Answer:

Effects Of The Planetary Winds On Earth:-

Planetary winds blow in a regular pattern throughout the year in fixed direction from regions of high pressure to regions of low pressure on the Earth. There are three types of planetary winds-trade winds, westerlies and Polar winds.

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Effects of the trade winds:

After collecting a sufficient amount of water vapour while blowing over the seas, the trade winds cause rainfall on the eastern margins of the continents. This favours agricultural activities there. For example, northeast Brazil, north- east Australia, and the Islands of Hawaii have favourable climatic conditions and agriculture has flourished there.

The trade winds blow from northeast in the northern hemisphere and south-east in the southern hemisphere.

After causing rainfall in the eastern parts, when these winds reach the western part of the continents, they lose most of their moisture content. So, these regions get very little rainfall and major deserts have developed here, such as the Sahara, the Kalahari, the Atacama, etc.

With their constant and defined path and speed, in the earlier times, these winds used to help in the navigation of ships and trade, thus earning the name trade wind.

Effects of the westerlies:

  1. The westerlies also collect sufficient moisture while blowing over the seas and cause precipitation on the western margins of the continents due to their direction of flow. These conditions also favour agricultural practices in those regions. For example, the land around the Mediterranean Sea.
  2. The westerly winds blow from south-west in the northern hemisphere and from north-west in the southern hemisphere. These winds cause less rainfall on the eastern parts of the continents situated along their way; but the middle parts receive moderate rainfall and thus, temperate grasslands have developed in such regions of the world. For example, the Prairies in North America, Pampas in South America, Steppe in Central Asia, Veld in South Africa and Downs in Australia are such temperate grasslands.

Effects of the polar winds:

Polar winds blow over the eastern part of the continents. Thus, the climate of the eastern margins of these continents become extremely cold and they experience regular snowfall.

The cold polar winds also cause snowstorms in the polar regions, for example blizzards in Antarctica.

Question 6. Explain the shifting of pressure belts.
Answer:

Shifting Of Pressure Belts:-

The pressure belts follow the apparent annual migration of the sun to the north on the Tropic of Cancer (on June 21) to the south on the Tropic of Capricorn (on December 22), reaching its points of zenith twice on the Equator (on March 21 and September 23).

On June 21, the sun is directly overhead on the Tropic of Cancer and all the pressure belts shift towards the north by 5°-10°. On December 22, the sun shines vertically over the Tropic of Capricorn and similarly, all the pressure belts move southward.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Shifiting of pressure belts

 

Winds are largely influenced by this shifting of the pressure belts during the annual migration of the sun. The changes that occur are more prominent in the lower latitudes than in the higher latitudes.

Effect:

Maximum effect of this shifting of the pressure belts is observed between 30° and 40° north and south latitudes, where the regions remain under the influence of trade winds in summer and westerlies in winter.

The eastern margins of the continents receive precipitation due to easterly trade winds while the western parts of those regions remain dry.

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For example, the southern part of Argentina and Sudan get rain while the western parts of the Mediterranean regions (such as south Chile) remain dry.

On the other hand, the same western areas get heavy rainfall under the influence of the westerlies in winter, while the eastern margins remain dry. As the pressure belts shift with changing of seasons, the belts of precipitation also change their positions.

Question 7. Discuss the different types of periodic winds.
Answer:

Different Types Of Periodic Winds:-

Unequal air pressure between land and water surfaces at a particular place, at a particular time or period, gives rise to periodic winds.

There are three types of periodic winds

  1. Sea breeze
  2. Land breeze and
  3. Seasonal winds.

1. Sea breeze:

The landmass, being warmer than the adjacent sea during the day, forms a low pressure area (almost a vacuum) above it. As a result, a comparatively cooler airblows over the sea.

This is called the sea breeze. The sea breeze often brings showers in the coastal regions.

2. Land breeze:

At night, the sea remains warmer than the adjacent land portion, which has already discharged its heat. The cool air over the land thus moves towards the warm sea.

This cool wind usually starts blowing at midnight or in the later part of the night and is called the land breeze.

3. Seasonal winds:

The difference temperature and air pressure on land and its adjacent water body causes winds to move towards land from the waterbodies or vice- versa. These winds change their direction season-wise, according to the prevailing conditions.

Hence, these are known as seasonal winds. They are also known as monsoon winds in India. The monsoon wind blows from south-west in summer and from north-east in winter.

In summer, the monsoon winds bring rain in India, while in winter, the monsoon winds are usually dry.

Question 8. What are local winds? Discuss some of the local winds.
Answer:

Local winds:

A difference in temperature and air pressure gives rise to certain winds that are influenced by the local topography and atmosphere of a particular place. These are called local winds. Example-Loo, Foehn, Chinook, Pampero, Sirocco, Khamsin, Andhi.

Some local winds:

Three local winds are discussed below

1. Loo:

It originates from the north-western landmass of India during the day. It is a very hot and dry wind that blows strongly over the land in a horizontal manner. Loo blows mainly over Delhi and parts of Rajasthan.

2. Foehn:

It is a dry and hot wind that blows down the leeward slope of the Alps in Europe. Foehn blows with great force. During spring, it melts the snow very quickly and thus helps in the luscious growth of pasture lands.

3. Chinook:

It is similar to Foehn, blowing eastward across the Prairies of North America from the eastern slope of the Rocky Mountains in the west. ‘Chinook’ in English means ‘snow eater’, as it increases temperature and melts the snow of the extended Prairie region. This wind strictly blows in winter.

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Question 9. How have the names like Aila, Thane, Phailin, Helen, Lehar, Haiyan, etc., come to mean various cyclonic storms?
Answer: Meteorologists name the cyclonic storms that occur in various places around the world.

For example, cyclones are known as

  1. Hurricane over the caribbean sea
  2. Typhoon in japan and south china sea
  3. Baguio in the philippines island, etc.

Similarly, the tropical cyclones in the Indian subcontinent are assigned different local names. These are Aila, Thane, Phailin, Helen, Lehar, etc. In the year 2000, the WMO (World Meteorological Organisation) decided to officially accept these local names.

It was decided that the cyclones originating in the Indian Ocean would be named by the countries around the ocean, including Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, and Thailand.

Each country will submit a list of probable names for the storms which will be arranged alphabetically according to the first letter of the country’s name and the names of the cyclones in this region will be chosen from the respective lists.

Example ‘Aila’ came from Maldives, Phailin or Pilin’ came from Thailand, ‘Lehar’ from India, ‘Hudhud’ from Oman, ‘Fani’ from Bangladesh, etc.

Question 10. Explain briefly the variable winds. Or, What are cyclones and anti- cyclones? Explain in brief.
Answer:

Variable Winds:-

The winds that suddenly cease after blowing for a short span of time, depending on the local air pressure, are called variable or irregular winds.

A drastic, unpredictable rise or fall of air pressure in highly localised area gives rise to sudden or irregular winds. These winds are mainly of two types

  1. Cyclones and
  2. Anti-cyclones.

1. Cyclones:

A cyclone is a low pressure system with winds blowing anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere. The pressure falls rapidly at the centre, with strong winds spiralling around it.

The isobars in this region are either circular or oval in shape. Cyclones can be of two types according to their origin and structure

  1. Tropical cyclones and
  2. Temperate cyclones.

Tropical cyclones:

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Upward moving air that moves towards the centre of a low pressure area at a high velocity and in a spiral manner is called Tropical cyclone.

These cyclones originate over seas and oceans in the tropical regions, between 16° and 24° latitudes in either hemispheres. It is known by different names in different regions.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Direction of wind Movement in a cyclone

 

It is called ‘Cyclone’ in the Arabian Sea and Bay of Bengal, “Typhoon’ in South and East China Sea, ‘Hurricane’ in the Caribbean Sea.

Temperate cyclones:

The hot and cold winds blowing between 35° and 65° latitudes on both sides of the equator meet and gives rise to a ‘front. Cold winds being heavy, descend downwards and fill up the place of the hot wind.

The warm air mass overrides the cold air as the former is lighter. It rises up in a spiral manner and this is known as temperate cyclone.

2. Anti-cyclones:

An anti-cyclone is a weather condition having high pressure at its centre, associated with calm and fine weather. The winds blow clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere.

Circular isobars prevail in these regions. They move very slowly, drifting or remaining stationary at times.

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WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Direction of wind Movement in a Anti-cyclone

 

Question 11. Compare among trade winds, westerlies and polar winds.
Answer:

Comparison among trade winds, westerlies and polar winds are

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Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds  Short Analytical Type Questions

Question 1. What makes wind blow?
Answer:

Wind Blow:-

Difference in air pressure causes movement of wind. As per the natural tendency, winds always blow from high-pressure zones to low-pressure zones to maintain the pressure balance in the atmosphere.

The difference in pressure between two areas is the main factor what makes wind blow. Solar energy has great impact on the wind movement too. The sun’s heat increases the temperature of the air mass, making it expand, rise and form low-pressure regions.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Wind Movement due to difference in air pressure

 

For example, the equatorial low-pressure belt attracts cold and heavy winds from the sub-tropical high-pressure belts. On the other hand if the difference in pressure is negligible, calm weather conditions prevail.

Question 2. What is centrifugal force?
Answer:

Centrifugal Force:-

The rotational force of earth is felt maximum at the equatorial region and is almost nil at the poles.

This rotation tends to deflect all free flowing objects outward while the gravitational pull attracts everything towards the centre of the earth. The force the centrifugal force.

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WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Centrifugal force

 

Question 3. What is Coriolis force?
Answer:

Coriolis Force:-

G.D. Coriolis, a renowned scientist, first observed a kind of a deflecting or distracting force that originates due to the rotation of the earth.

Winds and ocean currents are mainly influenced by this force and get deflected to the right in the northern hemisphere and to the left in the southern hemisphere.

This force was named Coriolis force. Coriolis force has the maximum effect at the poles and the minimum at the equator.

Question 4. Define Ferrel’s law.
Answer:

Ferrel’s Law:-

As the earth is a sphere, its rotational force is not uniform everywhere. It tends to decrease gradually towards the poles from the equator. Thus, winds cannot blow straight on the surface of the earth and have to move in a curved manner.

This deflection occurs in a definite way. As a result, winds deviate to the right in the northern hemisphere and to the left in the southern hemisphere.

This was established by the famous American meteorologist William Ferrel in 1856 and is which deflects everything outwards is called known as the Ferrel’s law.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Deflection of path of wind

 

Question 5. Explain Buys Ballot’s law.
Answer:

Buys Ballot’s Law:-

In 1857, a Dutch meteorologist Buys Ballot found that in the northern hemisphere if you stand facing the wind, there will be low pressure to your left and high pressure to your right.

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In the southern hemisphere, the situation is reversed. This relationship between wind movement and air pressure was first explained by him. Hence, it is known as Buys Ballot’s law.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Direction of wind Wind movement and air pressure

 

Question 6. Classify the wind system.
Answer:

Classification Of Wind System:-

Wind system of the earth can be classified mainly into four broad categories, which are further of many types. This has been represented in the chart below-

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Wind

 

Question 7. What are trade winds?
Answer:

Trade Winds:-

The planetary winds that blow from the sub-tropical high-pressure belts of both hemispheres constantly, following a definite path throughout the year, towards the equatorial low-pressure belts are called trade winds.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Trade winds

 

These tropical winds blow from north- eastern direction in the northern hemisphere and from south-eastern direction in the southern hemisphere.

Question 8. From which direction does the wind brings rain to our state? Or, Give an account of the direction of the rain-bearing wind in our state.
Answer:

Direction Of The Rain-Bearing Wind In Our State:-

The rain-bearing wind that brings showers to the state of West Bengal is the south-west monsoon wind. The Tropic of Cancer, which receives vertical sun rays during summer passes through West Bengal, making the state intensely hot in summer.

This heat forms a zone of extreme low pressure that attracts sea breeze from the adjacent Bay of Bengal which is called the south-west monsoon wind. These winds are very humid as they carry plenty of water vapour while blowing over the sea and cause heavy rainfall here.

The duration of the rainy season in our state depends on the period during which the south- west monsoon winds blow over the land.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Monsoon which blowing over west bengal

 

Question 9. Why have deserts formed in the western margins of the continents which fall in the path of the trade winds, while the western margins of the continents which are under the influence of the westerlies receive heavy rainfall? Or, Why are most of the deserts situated in the western margins of continents in tropical areas?
Answer:

Most Of The Deserts Situated In The Western Margins Of Continents In Tropical Areas:-

The trade winds in both hemispheres blow from the warm tropics to the very hot equatorial region. As a result, they heat up further and absorb a lot of water vapour.

As they are easterly winds they cause heavy shower in the eastern margins of the continents. When the winds move from east to west in summer, they keep losing moisture constantly and the amount of rainfall goes on decreasing towards the west, where precipitation becomes almost nil.

So, large deserts have developed in these regions in the west. The westerlies, on the other hand blow from the west to the east. These cause heavy rain in winter in the western margins of the continents, while keeping the eastern regions dry.

Question 10. Briefly write about ITCZ.
Answer:

ITCZ:-

The permanent equatorial low-pressure belt attracts trade winds from sub-tropical high-pressure belts in both the hemispheres. Hence, the equatorial low-pressure belt becomes a meeting or converging point of north-east and south-east trade winds. This zone is called the Intertropical Convergence Zone or ITCZ.

The region always has a high temperature and so the air in this zone heats up and rises. So, no horizontal movement of air is experienced here, making it a region of ‘calm’ called the doldrums.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds ITCZ in the months of jan and july

 

Question 11. What is the relationship between air pressure belt and wind movement?
Answer:

Elationship Between Air Pressure Belt And Wind Movement:-

Air moves because of the difference in air pressure. There are seven pressure belts which exist on earth. Among these, three are low-pressure belts, while the rest are high-pressure belts.

To keep a balance among these pressure belts, air moves from high-pressure belts to low-pressure belts.

Example

  1. Air from the sub-tropical high-pressure belts flows towards the equatorial low-pressure belt throughout the year. These are known as the trade winds.
  2. A steady flow of air occurs from the sub-tropical high-pressure belts to the sub- polar low-pressure belts. These are known as the westerlies.
  3. Cold and heavy air flows from the polar high-pressure belts to the sub-polar low-pressure belts. These are known as polar winds.

Question 12. Why are the higher slopes in Kullu and Kangra valleys of Himachal Pradesh more populated than the valley floors?
Answer:

Higher Slopes In Kullu And Kangra Valleys Of Himachal Pradesh More Populated Than The Valley Floors:-

At times slopes of mountains are found to be more densely populated than the valleys. Certain weather conditions produce a reversal of the normal rate of change in temperature with altitude and thus attract more people to settle there.

These conditions are as follows-

  1. During the day, the sun heats up the mountain slopes more intensely than the valleys.
  2. When the cold Katabatic wind descends and settles down in the valleys at night, the temperature of the valleys become colder than the mountain slopes.

For these reasons, the Kullu and Kangra valleys are less populated while the mountain slopes are more densely populated.

Question 13. Why have major grasslands developed in the eastern and central parts of the continents along the path of the westerlies?
Answer:

Major Grasslands Developed In The Eastern And Central Parts Of The Continents Along The Path Of The Westerlies:-

Usually waterbodies remain warmer than the landmasses in winter and the westerly winds collect abundant moisture from the seas while blowing over them and thus cause heavy rainfall in the western margins of the continents.

After this, they continue to become drier as they move towards the central and eastern parts of the continents. Due to less rainfall, temperate grasslands have developed on the eastern and central parts of continents along the path of the westerlies.

Question 14. Give the characteristics of the sea breeze.
Answer:

Some of the characteristics of sea breeze are as follows

  1. It is a local wind.
  2. The difference in temperature between land and adjacent waterbody generates sea breeze.
  3. It blows during the day from sea to land.
  4. The intensity of this breeze is usually strong and its intensity depends on the topography of the coastal region.
  5. This breeze starts blowing about four hours after sunrise and picks up some speed in the evening.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds sea breeze

 

Question 15. Mention the features of the land breeze.
Answer:

Land breeze has the following features

  1. It is a local wind.
  2. It blows as a result of the difference in temperature between sea and adjacent land.
  3. It blows at night from land to sea.
  4. It is weaker in intensity than the sea breeze.
  5. It picks up speed at dawn.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Land breeze

 

Question 16. Write the differences between land breeze and sea breeze.
Answer:

The differences between land breeze and sea breeze are as follows

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Differences between land and sea breeze

 

Question 17. Write a brief note on monsoon winds.
Answer:

Monsoon Winds:-

The word monsoon is derived from the Arabic word mausim meaning ‘season. Monsoon wind is a seasonal wind and is associated with the rainy season in our country.

This wind develops due to the difference in temperature and air pressure between landmass and adjacent waterbodies (the Arabian Sea and the Bay of Bengal). In summer, these winds blow from south-west to north-east and cause rainfall in India.

In winter, the same wind blows from land to sea from north-east to south-west (retreating monsoon). But during this time, it cannot much all over the country cause rain, as it does not contain moisture.

Question 18. Why is monsoon wind classified as seasonal or periodic wind?
Answer:

Monsoon Wind Classified As Seasonal Or Periodic Wind:-

Monsoon winds are almost similar to land and sea breezes, except for the fact that these (monsoon winds) are seasonal, rather than being a daily phenomena. This is so because-

1. The monsoon winds depend on the apparent annual migration of the sun. The sun remains overhead on the Tropic of Cancer on 21 June and during that time, the northern hemisphere experiences summer, while the southern hemisphere experiences winter.

When the northern hemisphere experiences summer, cold winds blow from the south towards a low-pressure zone. After crossing the equator, these winds gets deflected to the right as per Ferrel’s law, become the south- west monsoon winds and bring rain to India.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds summar, winter, monsoon wind movements

 

2. Again, on December 22, the sun being overhead on the Tropic of Capricorn, the monsoon winds blow from the opposite or north-east direction under reverse conditions.

So, it can be seen that the monsoon winds change their direction according to seasons and so are called seasonal or periodical winds.

Question 19. In which season does north wind blow over our country?
Answer:

As the sun migrates to the southern hemisphere in winter, India remains comparatively cold because it does not receive perpendicular sunrays during this time. The southern hemisphere experiences summer then.

The high-pressure zone that develops over the Indian landmass causes air to blow towards the warm, low-pressure zone of the southern hemisphere.

In our country, this wind blows from land to sea in the winter and is know as the north-east monsoon (retreating monsoon) wind. This wind is dry and is also called the north wind.

Question 20. What do you mean by ‘inversion of energy, the temperature rises. Due to this, the temperature’?
Answer:

Altitude and temperature vary inversely. This means, temperature normally decreases with an increase in altitude or height (at the rate of 6.4°C per 1000m).

There are, however, some places where certain weather conditions produce a reversal of normal lapse rate in the lower atmosphere. In these cases, temperature increases with an increase in altitude.

Usually, on a calm night with no cloud cover, winds from the upper layers start blowing down along the mountain slope. By discharging heat, this wind already becomes cool and heavy.

This type of wind is called Mountain wind or Katabatic wind. On the other hand, during daytime a type of warm wind which moves upward is called Valley wind or Anabatic wind. In such cases, the lower slopes of a mountain record less temperature than the upper ones.

This happens due to the ‘inversion of temperature. So, farmers sometimes prefer mountain slopes for their agricultural activities than the lower altitudes of the valleys.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Inversion Of Temperature

 

Question 21. Why does temperature of mountain slopes increase in spite of increase in altitude?
Answer:

Temperature Of Mountain Slopes Increase In Spite Of Increase In Altitude:-

Generally, temperature and altitude vary inversely. But in the valleys, if the sky has no cloud cover to prevent infiltration of solar air in the lower parts of the valley becomes warm and it starts to rise.

This warm air makes the mountain slopes warm. So, the temperature rises in the mountain slopes in spite of an increase in altitude.

Question 22. How do the winds get their names?
Answer:

Winds Get Their Names As Follows:-

A wind is named according to the direction from which it blows. Thus, a wind from the south blowing towards any direction is called a south wind.

For example, India receives rain from the monsoon winds that come from south-west and we call it south-west monsoon wind. Similarly, the westerlies have got their names from the direction from which they blow, i.e., the west.

Question 23. Write the differences between wind and air current.
Answer:

The differences between wind and air currents are

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Differences between wind and air current

 

Question 24. Write down the hemispheres in which these places are located and the winds that they experience:

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Hemisphere place Name of the wind

Answer: The hemispheres in which these places Beaufort Sea Northern are located and the winds that they experience are as follows

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Hemisphere place Name of the wind.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Short Answer Type Questions

Question 1. What do you mean by planetary winds?
Answer:

Planetary Winds:-

The existing permanent belts of high and low pressure on the earth’s surface cause winds to move in a regular pattern throughout the year along definite directions. These winds are called planetary winds. These are also called invariable or permanent or primary winds.

They are constant and are of three types

  1. Trade winds
  2. Westerlies and
  3. Polar winds.

Question 2. From which direction do the westerlies blow in the southern hemisphere and what is the name given to such winds?
Answer:

The westerlies in the southern hemisphere blow from the high-pressure belt around the Tropic of Capricorn to sub-polar low-pressure belt around the Antarctic Circle.

During their journey, they deflect towards the left as per Ferrel’s law and blow from the north-west. So, they are known as the north-west westerly winds.

Question 3. What are the westerlies?
Answer:

Westerlies:-

The winds that blow from the sub-tropical high-pressure belts to the sub-polar low-pressure belts in both hemispheres are called the westerlies.

Question 4. Why are the westerlies faster in the southern hemisphere?
Answer:

Westerlies Faster In The Southern Hemisphere:-

The westerlies are stronger or faster in the southern hemisphere as compared to the northern hemisphere. This happens because there are no large lamdmasses found in this region that can obstruct their path. So, here westerly winds are faster.

Question 5. Why is there almost no rainfall from the winter monsoon winds?
Answer:

There Is Almost No Rainfall From The Winter Monsoon Winds

In winter, monsoon wind blows from land to sea and it follows the direction from north-east to south-west (retreating monsoon).

As it blows from over the land, it does not contain much moisture to cause rainfall. Thus, there is almost no rainfall caused by the winter monsoon wind.

Question 6. From which direction does the polar wind blow in the southern hemisphere according to the Ferrel’s law and what is it called?
Answer:

The polar wind in the southern hemisphere blow from the Antarctic high-pressure belt to the sub-polar low-pressure belt of the southern hemisphere.

Along their path, they deflect towards the left as per Ferrel’s law and blow from the south-east. So, they are known as the south-east polar winds or polar easterlies.

Question 7. Why are trade winds also called ‘the winds of the traders or businessmen’?
Answer:

Trade Winds Also Called ‘The Winds Of The Traders Or Businessmen’:-

Trade winds blow between approximately 5° and 25° north and south latitudes. These winds rise from sub-tropical high-pressure belts and move towards the equatorial low-pressure belt. These are regular in terms of both speed and direction.

They seem to trace out a path in the sea for sailing in ancient times. Ships carrying goods for trading followed the path of these winds. So they are called ‘trade winds.

Question 8. What are the roaring forties?
Answer:

Roaring Forties:-

The north-west westerlies blow between 40° and 60° south latitudes uninterrup- tedly in the southern hemisphere because there are no large landmasses to obstruct them.

These winds blow with a great velocity and make loud noise while blowing over this region. Hence, these latitudes are known, by different names depending on the sound these winds make while blowing. The latitude of 40°S is known as the ‘roaring forties’.

Question 9. Why are the westerlies also called ‘anti-trade winds’?
Answer:

Westerlies Also Called ‘Anti-Trade Winds’:-

The rotational force of the earth has led to the formation of two low pressure belts along the sub-polar regions that attract winds from the sub-tropical high pressure belts in both hemispheres.

These are the westerlies, constant winds that blow in the opposite direction of the trade winds and are hence called the ‘anti-trade winds.

Question 10. Why do polar winds not cause rainfall?
Answer:

Polar Winds Not Cause Rainfall:-

According to meteorologists, both poles have two permanent high-pressure belts. Extremely cold and dry winds from the poles blow towards the adjacent sub-polar low-pressure belts, but these do not cause any rainfall because of the absence of considerable moisture in them.

However, the minimal moisture content of this wind gets precipitated as snow, instead of rain. Hence, polar regions have no rainfall but experience occasional snowfall.

Question 11. Why is the polar wind cold?
Answer:

Polar wind is cold, because

  1. The poles have permanent ice caps.
  2. The polar regions experience six months day and six months night alternately.
  3. These regions receive very slanted rays of the sun, which do not produce enough heat.

Question 12. Which wind brings more rainfall to coastal areas?
Answer:

Wind Brings More Rainfall To Coastal Areas Are Given Below:-

Sea breeze, the kind of wind with maximum water vapour content, causes heavy rainfall in the coastal regions. Sea breeze blows during the day from the comparatively cooler water bodies towards the adjacent hotter landmasses.

This is because the air above the landmasses gets heated up and rises, thus creating a vacuum. The moisture-bearing winds from the sea fills in the vacuum and cause rainfall.

Question 13. From which direction would the cool breeze come in a coast or a river bank in the evening?
Answer:

Direction Of Cool Breeze Come In A Coast Or A River Bank In The Evening

In the evening, a cool, moist breeze blows from the river bank or coastal area towards the land.

This happens because of continuous incoming solar rays form a hot low-pressure zone over the landmass; whereas the waterbody, being comparatively less heated, has a high-pressure zone above it.

Therefore, by normal standards, winds blow from high-pressure to low-pressure zones.

Question 14. Which wind would help boats sail as they venture out into the sea or river at dawn?
Answer:

Wind Would Help Boats Sail As They Venture Out Into The Sea Or River At Dawn:-

Once the sun sets, both the land and waterbodies start discharging heat. The solid landmass can do it more rapidly than the liquid waterbody and as a result, high pressure exists over the land while low pressure prevails over the waterbodies.

So the wind blows towards the sea. This is known as land breeze. At dawn, the difference in temperature between land and sea is maximum. So land breeze is most intense at dawn.

Thus, this wind would help boats sail as they venture out into the sea or river.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Multiple Choice Questions Choose The Correct Option

Question 1. Air movement chiefly depends on-

  1. Atmospheric pressure
  2. Temperature
  3. Latitudinal location
  4. Altitude of land

Answer: 1. Atmospheric pressure

Question 2. Coriolis invented the relationship between the earth’s rotation and centrifugal force of objects on earth in-

  1. 1857
  2. 1835
  3. 1873
  4. 1880

Answer: 2. 1835

Question 3. The relationship between air pressure and wind system was established by-

  1. Ferrel
  2. Buys Ballot
  3. Magellan
  4. Coriolis

Answer: 2. Buys Ballot

Question 4. Buys Ballot was a-

  1. Dutch meteorologist
  2. German geographer
  3. French geologist
  4. Russian meteorologist

Answer: 1. Dutch meteorologist

Question 5. The direction of wind is measured by a-

  1. Barometer
  2. Rain gauge
  3. Wind vane
  4. Hygrometer

Answer: 3. Wind vane

Question 6. The unit ‘knot’ is generally used to express-

  1. Wind direction
  2. Air pressure
  3. Wind velocity
  4. Chumidity

Answer: 3. Wind velocity

Question 7. The wind that blows regularly throughout the year from a definite direction between 5° and 25° north and south latitudes is called-

  1. Polar wind
  2. Trade wind
  3. Westerlies
  4. Monsoon wind

Answer: 2. Trade wind

Question 8. The trade wind usually travels at a speed of-

  1. 10-12km/hr
  2. 35-40km/hr
  3. 16-30km/hr
  4. 40-45km/hr

Answer: 3. 16-30km/hr

Question 9. The major deserts of the world lie in the-

  1. Path of the planetary winds
  2. Way of the westerlies
  3. Direction of the trade winds
  4. Path of the south-west monsoon wind

Answer: 3. Direction of the trade winds

Question 10. An example of a planetary wind is-

  1. Westerlies
  2. Sea breeze
  3. Monsoon wind
  4. Land breeze

Answer: 1. Westerlies

Question 11. Westerlies in the southern hemisphere blow from-

  1. South-east
  2. South-west
  3. North-east
  4. North-west

Answer: 4. North-west

Question 12. Polar easterlies blow in both hemispheres within-

  1. 70° 80° latitudes
  2. 5°-25° latitudes
  3. 40°-45° latitudes
  4. 35°-60° latitudes

Answer: 1. 70° 80° latitudes

Question 13. Portugal, Spain, Italy and France receive rain in winter due to the influence of the

  1. North-west westerlies
  2. South-west westerlies
  3. South-west monsoon winds
  4. North-east monsoon winds

Answer: 2. South-west westerlies

Question 14. The polar wind is-

  1. Warm and wet
  2. Cold and dry
  3. Cold and wet
  4. Warm and dry in nature

Answer: 2. Cold and dry

Question 15. A wind that blows seasonally is called-

  1. Planetary wind
  2. Sea breeze
  3. Sudden/irregular wind
  4. Monsoon wind

Answer: 4. Monsoon wind

Question 16. The cold heavy and moist wind that blows from the sea to land during the day is called

  1. Abrupt or sudden wind
  2. Land breeze
  3. Sea breeze
  4. Trade wind

Answer: 2. Sea breeze

Question 17. During the rainy season, India receives rain from-

  1. North-east monsoon winds
  2. South-east monsoon winds
  3. South-west monsoon winds
  4. North-west monsoon winds.

Answer: 3. South-west monsoon winds

Question 18. An example of a local wind is-

  1. Monsoon wind
  2. Sea breeze
  3. Trade wind
  4. Loo

Answer: 4. Loo

Question 19. Which of the following wind is known as ‘the Doctor’?

  1. Foehn
  2. Pampero
  3. Harmattan
  4. Bora

Answer: 2. Pampero

Question 20. The ‘Sirocco’ blows over-

  1. Libyan desert
  2. The alps
  3. The rocky mountains
  4. The himalayas

Answer: 1. Libyan desert

Question 21. The eye of an anti-cyclone has-

  1. High pressure
  2. Medium pressure
  3. Low pressure
  4. Equal pressure

Answer: 1. High pressure

Question 22. An example of a downslope wind is-

  1. Anabatic wind
  2. Trade wind
  3. Katabatic wind
  4. Monsoon wind

Answer: 3. Katabatic wind

Question 23. The warm and dry wind that blows down to the Prairies from the Rocky Mountains of North America is called-

  1. Bora
  2. Chinook
  3. Foehn
  4. Loo

Answer: 2. Chinook

Question 24. The cyclone that occurs in the islands of West Indies is known as-

  1. Typhoon
  2. Tornado
  3. Hurricane
  4. Phailin

Answer: 3. Hurricane

Question 25. A typhoon is-

  1. An abrupt/sudden wind
  2. Planetary wind
  3. A seasonal wind
  4. A local wind

Answer: 1. An abrupt/sudden wind

Question 26. The word ‘Chinook’ literally means-

  1. Doctor
  2. Season
  3. Snow eater
  4. Grass eater

Answer: 3. Snow eater

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Very Short Answer Type Questions Fill In The Blanks

Question 1. Winds usually blow from a _______ pressure belt to a _______ pressure belt.
Answer: High, low

Question 2. _______ wind is heavy and so the corresponding air pressure is high.
Answer: Cold

Question 3. _______ force is generated due to the rotation of the earth.
Answer: Centrifugal

Question 4. The rotation of the earth causes _______ effect.
Answer: Coriolis

Question 5. As per Ferrel’s law, winds in the northern hemisphere deflect to the _______ direction.
Answer: Right

Question 6. The vertical movement of air mass on earth is called _______.
Answer: Air current

Question 7. Air current in the equatorial region always moves _______.
Answer: Upward

Question 8. The winds that blow towards a definite direction throughout the year, are called _______ winds.
Answer: Planetary

Question 9. The meaning of the term ‘trade’ is _______.
Answer: Path/way that is steady

Question 10. North-east trade wind records a speed of _______ km/h on an average.
Answer: 16

Question 11. The _______ wind is considerably weaker in the northern hemisphere.
Answer: Trade

Question 12. _______ is a desert that has developed in the path of the trade wind.
Answer: Sahara

Question 13. The _______ blow in the opposite direction of the trade winds.
Answer: Westerlies

Question 14. Another name for the westerlies is _______.
Answer: Anti-trade wind

Question 15. _______ westerlies blow in the northern hemisphere and polar wind blows in the southern hemisphere.
Answer: South-west,south-east

Question 16. The westerlies cause more rainfall in the _______ season.
Answer: Winter

Question 17. The 50° south latitude is called _______.
Answer: Furious Fifties

Question 18. The places that lie along the pathway of the westerlies receive maximum rain in _______.
Answer: Winter

Question 19. The _______ wind causes blizzards.
Answer: Polar

Question 20. Sea breeze is a kind of _______ wind.
Answer: periodical

Question 21. Sea breeze blows during the _______.
Answer: Day

Question 22. Land breeze blows during.
Answer: Night

Question 23. Foehn is a type of _______ wind.
Answer: local

Question 24. A spiraling upward thrust of wind towards a low pressure eye at the centre is called _______.
Answer: Cyclone

 

Write True Or False

Question 1. Tornado is a local wind.
Answer: False

Question 2. With the change of seasons atmospheric pressure belts shift about 10°-15° in both the hemispheres.
Answer: False

Question 3. The major deserts in the world are locatedMatch the columns in the eastern margins of continents.
Answer: False

Question 4. Planetary winds are of four types.
Answer: False

Question 5. Shifting of planetary winds is noticed mostly in the region between 40° and 50° latitudes in either side of the equator.
Answer: False

Question 6. North-west westerlies are also called ‘brave west winds’.
Answer: True

Question 7. The direction of the trade winds depends on the equatorial low pressure belt.
Answer: False

Question 8. The polar winds. in the southern hemisphere are less forceful.
Answer: False

Question 9. ITCZ is the converging region of north-west and south-west westerlies.
Answer: False

Question 10. The trade winds are more forceful in the northern hemisphere than in the southern hemisphere.
Answer: False

Question 11. The Mediterranean climatic region is influenced by the trade winds in summer and the westerlies in winter.
Answer: True

Question 12. The westerlies cause rainfall in the western margins of the continents of the temperate region.
Answer: True

Question 13. Coriolis force is maximum at the poles and minimum at the Equator.
Answer: True

Question 14. Winds always blow from low-pressure belts to high-pressure belts.
Answer: False

Question 15. Winds are named after the direction from which they blow.
Answer: True

Question 16. Warm air has greater capacity to hold moisture and so is light or less dense.
Answer: True

Question 17. The horizontal movement of air, more or less parallel to the earth’s surface, is called wind.
Answer: True

Question 18. If moving wind in the northern hemisphere hits us from the back, we would feel more pressure on the right side than on the left side.
Answer: True

 

Match The Columns

1.WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Match the following

Answer: 1. C, 2. D, 3. A, 4. B

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Answer In One Or Two Words

Question 1. Which movement of the earth forces winds to get deflected?
Answer: Rotation of the earth.

Question 2. Which force is responsible for the deflection of winds?
Answer: Coriolis force.

Question 3. Which factor determines the moisture-retaining capacity of an air mass?
Answer: Temperature.

Question 4. Name the unit used to measure the velocity of wind.
Answer: Knot.

Question 5. Which planetary wind is known for maritime commercial activities?
Answer: Trade wind.

Question 6. What is the trade wind known as in the southern hemisphere?
Answer: South-east trade wind.

Question 7. Which part of the continents receives rain under the influence of the trade winds?
Answer: The eastern part.

Question 8. Under the influence of which wind system have the Sahara and Kalahari deserts come into existence?
Answer: The trade winds.

Question 9. Give the full form of ITCZ.
Answer: Inter Tropical Convergence Zone.

Question 10. Which wind would bring rain to Portugal, Spain, Italy and France and in which season?
Answer: The westerlies, in winter.

Question 11. How far do the atmospheric pressure belts shift seasonally?
Answer: 5°-10° to the north or south.

Question 12. Name the wind that causes rainfall in the coastal region.
Answer: Sea breeze.

Question 13. Which breeze will help a sailboat to move in the river or in the sea, early in the morning?
Answer: Land breeze.

Question 14. Which winds are considered to be a larger-scale version of the land and sea breezes?
Answer: Monsoon winds.

Question 15. From which direction does the cold breeze come in a coast or a river bank in the evening?
Answer: From the sea or a river to the adjacent landmass.

Question 16. Name the local wind that blows along the Adriatic Bay.
Answer: Bora.

Question 17. Hurricane is an example of what kind of wind?
Answer: A sudden or irregular wind.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Conceptual Questions And Answers

 

Who am I?

Question 1. I am a belt that divides the earth into two equal hemispheres. I have upward air current but no horizontal movement of air is prevalent. I am a belt of calm.’- Who am I?
Answer: Doldrums

Question 2. ‘I occur in the tropical regions between 25°-35° North and South latitudes. I was infamous for obstructing the smooth passage of ships from Europe and Middle East. Who am I?
Answer: Horse latitudes

Question 3. ‘I am a deflecting force that can change the direction of all freely moving objects on the earth’s surface in accordance with the rotation of the earth. Who am I?
Answer: Coriolis force

Question 4. I am a region along the equator where the north-east and south-east trade winds meet.’-Who am I?
Answer: ITCZ

 

Scrambled Words

1. RDLUDOSM
2. LSWERTIESE
3. IARORGNTFROSIE
4. EABSEZREE
5. ABNATICA
6. W DLCIONLA
7. MTAHATRNA

Answers:

1. DOLDRUMS
2. WESTERLIES
3. ROARING FORTIES
4. SEA BREEZE
5. ANABATIC
6. LOCAL WIND
7. HARMATTAN

 

Fill Up The Blanks In The Knowledge Hive

Question 1. Fill in the knowledge hive with information on trade winds.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Fill the blanks

 

Answers:

1. It blows from the high-pressure belts of the tropics towards the Equatorial low-pressure belt throughout the year.
2. North-east trade winds blow at a speed of 16km/hr and south-east trade winds blow at a speed of 22-30 km/hr.
3. The convergence point of the northeast and south-east trade winds is known as Doldrums.
4. Deserts have formed in the western margin of the continents in the northern hemisphere due to the impact of northeast trade winds.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Answer With Reference To The Illustration

Question 1. In order to travel from A (New York) to B (London) the pilot of an aircraft follows the path of movement of the south-west westerlies. So, can you tell which wind’s path of movement will a pilot from any temperate region follow to go from A (New York) to B (London)?

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Newyork to London direction map

Answer: The pilot of the temperate region will follow the direct path of the south-west westerlies.

Question 2. Mark the directions in each hemisphere in which winds will be deflected according to the Ferrel’s Law, with arrow lines.
Answer:

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Ferrels law with arrow lines

 

Question 3. Write the names of winds marked as 0, 0, 3, 4, 5, 6 in the correct places. Mark the path of movement with ‘-‘symbol.
Answer:

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds different types of winds

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds different types of winds.

 

Question 4. Look at the pictures below and identify which one illustrates the effect of a cyclone and which one that of an anti-cyclone.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Anti cyclone and cyclone

 

Answers:

  1. Anti-cyclone (because of the calm atmosphere)
  2. Cyclone (because of stormy weather)

Question 5. From the following two diagrams identify the wind direction in the northern and southern hemispheres during an anti-cyclone.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Anti cyclone

Answers:

  1. The clockwise direction of winds in the northern hemisphere is found during anti-cyclone.
  2. The anti-clockwise direction of winds in the southern hemisphere is found during anti-cyclone.

Question 6. From the two diagrams given below to determine the direction of the winds of cyclones in the northern and southern hemispheres.

WBBSE Class 8 Geography Chapter 4

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds cyclone

Answers:

  1. The anti-clockwise direction of winds in the northern hemisphere is found during cyclones.
  2. The clockwise direction of winds in the southern hemisphere is found during cyclones.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Crossword

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds crossword

CLUES

Down:

1. Severe tropical storm that forms in the Caribbean Sea.
2. A hot, dry wind local to Egypt and Saudi Arabia.
5. The region where north-east and south-east trade winds meet.

Across:

3. Force that appears to deflect winds.
4. Local wind in the Gulf of Guinea.

Answers:

Down: 1. Hurricane, 2. Khamsin, 5. ITCZ
Across: 3.Coriolis, 4. Harmattan

WBBSE Class 8 Geography Chapter 4

Advanced Questions And Answers

Question 1. How is the velocity or speed of wind measured?
Answer:

Velocity Or Speed Of Wind Measured As Follows:-

The instrument used to measure the speed or velocity of wind is called Anemometer. In this instrument, four semi-circular bowls are fixed on a tall pole in such a manner that the bowls can move freely, being attached to a pair of crossed sticks.

A measuring instrument, almost like a watch, is fixed at the bottom of the pole to measure the speed of wind. As the wind blows, the bowls move freely.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Anemometer

 

Question 2. Name the winds under the influence of which China in Asia, Ethiopia in Africa and Mexico’ in North America receive rainfall.
Answer:

Question 3. Dark clouds are looming over till late in the year! Do you think the advent of the rainy season is getting progressively delayed every year?
Answer:

Dark clouds are looming over till late in the year:-

The dark clouds during the month of October is indeed a matter of concern. The south-west monsoon wind should ideally return by September. According to experts, human beings are directly or indirectly responsible for this phenomenon.

The use of fossil fuels, deforestation, population explosion and an excessive increase in number of factories are some of the factors responsible for global warming as per expert’s opinion.

As a result of global warming, the atmosphere is getting heated up and temperature is increasing. Consequently, the polar ice caps are melting. Due to the melting of the polar ice caps, excess water vapour is being added to the air.

This results in chances of rainfall over a longer period of time. Thus the entire pattern of season change is getting affected. These are the reasons for the sighting of dark clouds even in October.

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Formative

Participation

This segment will indicate how much the students have actively participated and taken initiative during the class.

Suppose you are facing the wind in the southern hemisphere. Fill up the blanks in the picture below to describe air pressure conditions arround yourself.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Air pressure conditions

 

Empathy And Cooperation

This segment will determine the ability of students to cooperate, and help others within a group.

Question 1. The students will be divided into two teams, A and B. First, team A will ask questions and team B will answer them. Later, team B will ask questions and team A will answer them.

Answer:

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Team A questions, B Answers

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Team B questions A answers

 

Aesthetics And Creativity

This segment will check the aesthetic sense and creativity of the students.

Question 1. Collect information on recent cyclonic events in our state and our country and prepare reports on them.
Answer:

Name: Saswata Choudhury
School: Balagarh High School
Class: VIII
Sec: A
Roll: 10
Project: A report on a cyclone that has occurred recently

Introduction:

Temperature difference in different parts of the earth creates differences in air pressure. Since waterbodies are vast in number in the tropical areas as well as landmasses, change of air pressure is quite normal in this area and this region is prone to cyclonic storms.

A cyclonic storm is perilous to human beings as well as to any living being. Such a cyclonic storm, named Fani, lashed India’s east coast on 3 May 2019.

WBBSE Class 8 Geography Chapter 4

Description of the Cyclone:

Fani left a trail of destruction along the country’s east coast, mainly the coastal areas of Odisha and West Bengal. The velocity of wind in this storm was 215 km/h. Warnings in advance and proper evacuation saved thousands of lives.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds College related to cyclone Fani

 

However, homes were destroyed, trees and telegraph poles were uprooted and 89 people were killed by this storm among them 64 people was from Odisha. Odisha tourism and Puri temple faced severe destruction during this storm.

Electric supply was completely cut off in Fig. Collage related to cyclone Fani the coastal regions of Odisha. Drinking water got contaminated. The storm subsequently weakened while moving to West Bengal and Bangladesh.

The government and different NGOS did a splendid job by providing shelter and supplying food to the distressed people.

Question 2. Write down the names of the winds which have their paths traced by this arrows. Permanent wind blowing
Answer:

WBBSE Solutions For Class 8 Geography Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Permanent wind blowing on the earth surface

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