WBBSE Solutions For Class 8 Geography Chapter 4 Pressure Belts And Wind Movement Topic A Pressure Belts And Winds

Chapter 4 Pressure Belts And Wind Movement Synopsis

Air has weight and so it exerts pressure. This is called air pressure.

Belts of air of similar pressure stretching for thousands of kilometres, horizontally surround the earth. These are known as pressure belts.

The equatorial low-pressure belt is located between 5°N and 5°S latitudes, i.e., on either side of the equator.

The horizontal movement of air on the surface of the earth is called wind.

The vertical movement of air over the surface of the earth is called air current.

In the equatorial region, warm and light air moves upward. Thus, no wind movement parallel to the earth’s surface is noticed here. This leads to the prevalence of calm condition here. So, this region is known as belt of calm or doldrums.

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Sub-tropical high pressure belts extend between the latitudes 25° and 35° in both the hemispheres.

During the sixteenth century ships from the West Indies and Europe used to come to standstill conditions while sailing through the sub-tropical regions because of the presence of the calms. In such circumstances to save food and drinking water, the crew had to sacrifice their horses by throwing them into the Atlantic Ocean. So the sub-tropical regions are known as horse latitude.

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The sub-polar low-pressure belts are located between 60° and 70° latitudes in both hemispheres. These belts are called the Arctic sub-polar pressure belt and Antarctic sub-polar pressure belt in the northern and southern hemisphere respectively.

The polar high-pressure belts are located between 80° and 90° in both the hemispheres.

Wind always blows from high-pressure to low-pressure areas in order to maintain the balance of pressure.

Due to the rotation of the earth, a force deflects the direction of winds. This deflective force is known as the Coriolis force.

Due to the Coriolis force, winds are deflected to the right in the northern hemisphere and to the left in the southern hemisphere. This law is popularly known as Ferrel’s law.

According to Buys Ballott’s law, in the northern hemisphere, if you stand facing the wind, there will be low pressure to your left and high pressure to your right. In the southern hemisphere, the situation will be reversed.

The winds blowing almost in the same. direction at regular intervals throughout the year over a large area are called planetary winds or permanent winds.

Planetary winds are of three categories- Trade winds, Westerlies and Polar winds.

The winds blowing from the northern and southern sub-tropical high pressure belts to the equatorial low pressure belt constantly throughout the year are known as trade winds.

North-east trade winds and south-east trade winds meet at the equatorial low-pressure belt. Thus this region is also known as the equatorial calm region or Intertropical Convergence Zone (ITCZ).

The permanent winds that blow from the sub-tropical high pressure belts (25°-35°) to the sub-polar low pressure belts (60°- 70° in both the hemisphere) are known as the westerlies. These winds blow from 35°-60° latitudes in both the hemispheres.

The velocity of the westerlies is very high in the southern hemisphere. So, the westerlies blowing with a howl along the 40°S, 50°S and 60°S latitudes are called roaring forties, furious fifties and screaming sixties respectively.

The permanent winds blowing from polar high pressure belts to the sub-polar low pressure belts are known as polar winds. These winds blow from 70°-80° latitudes in both the hemispheres.

The winds that periodically change their direction diurnally or seasonally are called secondary or periodic winds.

The wind blowing from the sea towards the land during the day time, is known as sea breeze. By mid-afternoon, when the temperature is maximum, the sea breeze blows at its maximum speed.

Land breeze, on the other hand, blows from the land towards the sea mainly at nights, attaining maximum speed in the early morning.

Monsoon winds are the seasonal version of land breeze and sea breeze.

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Summer monsoon wind comes from the south-western direction. It is hot and humid, so it brings rain.

The branch of the monsoon wind that blows from the north-east, is called winter monsoon wind. As it is a dry and cool wind, it does not cause rainfall in most parts of the country.

During the day, warm wind moves up along the slope of a mountain valley since the temperature in the valley is warmer than the surrounding air. This wind is called Anabatic wind.

At night, cold wind moves down the slope of a mountain valley since temperature in the valley is cooler than the surrounding air. This wind is called Katabatic wind.

Local winds are small scale convection winds of local origin caused by temperature differences. Examples of some local winds are- Chinook (warm wind in the Rocky Mountains), Bora (cold and dry wind along the Adriatic Sea), Sirocco (warm and dry wind in Libya) and Loo (warm wind in India).

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

A cyclone is a large air mass that rotates around a strong centre of low atmospheric pressure. They can develop both in the tropical and temperate regions.

Anti-cyclone is a large scale circulation of winds around a region of high atmospheric pressure. It generally develops in the high latitudes with clear sky, drier air and sunny weather.

Chapter 4 Topic A Pressure Belts And Winds Analytical Type Questions

Question 1. Discuss the factors responsible for differences in air pressure.
Answer:

Factors Responsible For Differences In Air Pressure:-

Several factors are responsible for the differences in air pressure.

Some of these are

1. Temperature:

Temperature and air pressure vary inversely. As temperature increases, air expands, becomes less dense and exerts less pressure. Thus, a low-pressure belt exists in the hot equatorial region, while high pressure belts have formed in the cold polar regions of both the hemispheres.

2. Presence of water vapour:

Temperature and moisture content of the air vary proportionately. The hotter the air, more will be its water vapour content. Hot, moist air has low pressure as it is lighter than dry, cold air.

A certain volume of dry air contains more nitrogen and oxygen while the same volume of humid air contains comparatively less nitrogen and oxygen, making the humid air lighter than the dry one.

Hence, the equatorial region, which receives almost vertical rays of the sun throughout the year has hot and humid weather. It is a low-pressure belt while the polar regions are high-pressure zones due to the absence of more water vapour.

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3. Altitude:

Altitude and air pressure also vary inversely. As we move towards in the upward direction, we can feel less air pressure. This is because, with increase in height, the air becomes thinner or less dense.

4. Rotation of the earth:

The difference in air pressure is also a result of the rotational force of the earth. For example, the rotational velocity of the earth is slightly higher in the sub-polar regions than the polar regions.

This is why the winds from the sub-polar regions are deflected outward. As a result, the air in the said region is lighter and low-pressure belts have developed in these regions.

5. Density of the atmosphere:

Air pressure increases or decreases with the change in the density of the atmosphere. This density is not same throughout everywhere.

6. Distribution of land and water surface:

During the day, landmasses get heated rapidly and develop a low-pressure zone over there. At the same time high-pressure zone prevails over the seas where the temperature is comparatively cooler.

So the wind blows from the sea towards the land. In cold regions and at night, it is just the reverse.

Question 2. Explain with a labelled diagram the distribution of pressure belts in the world.
Answer:

Distribution Of Pressure Belts In The World:-

Depending on the differences in temperature, altitude, water vapour content, density of the atmosphere and rotational force of the earth, there exists a pattern of alternate high and low-pressure belts over the earth.

There are seven pressure belts-Equatorial low-pressure belt, a sub-tropical high-pressure belt of the northern hemisphere, sub-tropical high-pressure belt of the southern hemisphere, sub- polar low-pressure belt of the northern hemisphere, sub-polar low-pressure belt of the southern hemisphere, polar high-pressure belt of the northern hemisphere and polar high-pressure belt of the southern hemisphere.

Equatorial low-pressure belt:

This region between 5° north and south latitudes on both sides of the equator remains very hot throughout the year and thus developing a low-pressure zone. There is no horizontal movement of air.

The hot air rises upwards, making it a region of calm or doldrums.

Causes of formation:

  1. This region receives more or less vertical sun rays throughout the year.
  2. In the equatorial region, the area under waterbodies is greater than that of land surface. Thus, the air remains very humid.
  3. Deflection of winds occur towards the right in the northern hemisphere and left in the southern hemisphere as per Ferrel’s law.

Sub-tropical high pressure belts:

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This region lies between 25° and 35° north and south latitudes on either side of the equatorial low pressure belt.

Causes of formation:

  1. The hot, moist and light air from the equatorial region rises upward; gets cooled down and becomes heavier. After that it descends on the sub-tropical belts due to the deflection caused by the rotation of the earth. Thus forms a high pressure belt around this region.
  2. Air from the cold polar regions, while moving towards the equator, also descends here as a result of Coriolis force. This adds to the existing high pressure in this region.

Sub-polar low pressure belts:

These are sub-polar low pressure belts in the vicinity of 60°-70° north and south latitudes.

Causes of formation:

  1. These are mainly formed due to the rotation of the earth. The velocity of earth’s rotation is greater here than at the poles. Thus, the air gets deflected to the polar and sub-tropical regions. So volume and density of air decreases over the sub-polar region.
  2. These are the convergence zones of the cold Polar winds and warm Tropical winds, where the warm air is forced to rise and this causes low pressure.

Polar high pressure belts:

Beyond the polar regions, air pressure increases with increasing latitudes. So, high pressure belt exists in both the poles between 80° and 90° latitudes.

Causes of formation:

  1. Polar regions havepermanent ice caps and temperature remains below freezing point throughout the year. Hence, the air is always supercool, dense and heavy there.
  2. The rate of evaporation is almost nil as these regions get oblique rays of the sun. So, the air is not humid, but dry.
  3. The air that rises from the sub-tropical low pressure belt gets cooled, becomes heavier and descends in the polar regions. This adds to the existing high pressure in this region.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Pressure belts on the earths surface

 

Question 3. Substantiate the causes of formation of the equatorial low pressure belt and sub-tropical high pressure belts.
Answer:

Formation of the equatorial low pressure belt:

On either side of the equator, between 5° north and south latitudes, occurs this permanent low pressure belt.

This low pressure belt has formed due to three main reasons

  1. The region receives almost vertical rays of the sun throughout the year. The hot and light air, in turn, forms a low pressure belt in this area.
  2. The region has an extensive area under water surfaces and so the amount of moisture in the air of this region is high. The air pressure is less here due to high amount of moisture, which makes the air lighter.
  3. Since the effect of the earth’s rotation is maximum at the equator, winds usually rise and get deflected to the right in the northern hemisphere and to the left in the southern. hemisphere. This process decreases its density and an area of low pressure is formed.

There is hardly any horizontal movement of air. Thus, the region is also called the equatorial doldrums.

Formation of the sub-tropical high pressure belts:

These permanent high pressure belts have formed between 25° and 35° north and south latitudes.

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The reasons behind the formation of these belts are

  1. The hot and light winds from the equatorial low pressure zone rise, become cooler and heavier and sink down to settle. Due to the rotation of the earth, these winds get deflected to the right (in the northern hemisphere) or the left (in the southern hemisphere) and finally settle down around 25°-35° north and south latitudes, thus forming two permanent high pressure belts at the tropics.
  2. Cold, dry and heavy polar winds which are moving towards the equatorial belt also settle between these latitudes due to the rotation of the earth. Thus the volume of the air increases over this region.

There is alomost no horizontal movement of air in these belts. Hence, they are also called sub-tropical belts of calm.

Question 4. Why is air denser in the tropics and at the poles?
Answer:

Air is denser in the tropics for the following reasons

  1. The hot and light wind that rises from the equatorial low pressure belt gets cooled, becomes heavier and sinks down near the tropics.
  2. A portion of the cold and dense polar wind also settles down in the tropics during their movement towards the equatorial low pressure belt.

Air is denser at the poles due to the following reasons

  1. The poles have the perpetual ice caps, making these regions extremely cold with heavy air.
  2. Slanting sun’s rays fall on the Arctic and and the Antarctic Circles (662° north and south latitudes), which cannot heat the air significantly. Moreover, the poles experience six months of day and six months of night alternately, and thus remain cold. Thus, the air is cold and heavy.
  3. The rate of evaporation being very low here, the air remains dry and heavy.
  4. The wind that rises from the sub-polar low pressure belts also sink down near the poles after getting cooled at higher levels of the atmosphere.

Chapter 4 Topic A Pressure Belts And Winds Short Analytical Type Questions

Question 1. How is temperature and air pressure related?
Answer:

Temperature And Air Pressure Related As Follows:-

Temperature and air pressure are inter- related. We find that an increase in temperature forces air to expand. Thus, the air becomes lighter and rises upwards. As a result, low pressure develops.

Example-The equatorial region experiences low pressure as it receives almost perpendicular sun rays throughout the year. So a permanent low pressure belt has developed there.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Relationship between temperature and air pressure

Similarly, a decrease in temperature causes air to contract, become cold and heavy and develop high pressure.

Example-the poles have permanent high pressure belts. This is because the regions have ice caps and receive highly slanted rays of the sun and that too for a very short period of time.

Question 2. Identify the world pressure belts on the following diagram and write down their names in your answer book.

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Latitude Strecth

Mark the high and low pressure belts with different colours in a diagram and mention the latitudinal stretch of each pressure belt and locate them in the diagram.
Answer:

In this diagram the world pressure belts are as follows

  1. Equatorial low pressure belt
  2. Tropical high pressure belt of the northern hemisphere
  3. Tropical high pressure belt of the southern hemisphere
  4. Sub-polar low pressure belt of the northern hemisphere
  5. Sub-polar low pressure belt of the southern hemisphere
  6. Arctic high pressure belt and
  7. Antarctic high pressure belt.

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Pressure belts on the earths surface

 

Question 3. Why are sub-tropical high pressure belts around the Tropic of Cancer and the Tropic of Capricorn called tropical doldrums? Or, Why are the sub-tropical belts of northern and southern hemispheres found to be calm?
Answer:

Sub-Tropical Belts Of Northern And Southern Hemispheres Found To Be Calm:-

The sub-tropical high pressure belts around the Tropic of Cancer and the Tropic of Capricorn are called tropical doldrums, because-

  1. These two are high pressure belts and hot, rising winds from the equatorial region sink around these belts, after cooling and becoming heavier, when they reach higher altitudes.
  2. Due to earth’s rotation, cold and heavy air moving from the poles to the equatorial low pressure belt, sinks partially at these high pressure belts of the tropics.

Horizontal movement of air is not much observed here. As the atmosphere is calm, these regions are called sub-tropical belts of calm or doldrums.

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WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Tropical doldrums

 

Question 4. Why are the sub-tropical high pressure belts called ‘horse latitudes’? Or, Why would ships come to a standstill in the horse latitudes?
Answer:

Ships Come To A Standstill In The Horse Latitudes:-

Sub-tropical high pressure belts are found in the regions lying between 25° and 35° latitudes in both northern and southern hemispheres. Cold and heavy winds sink and settle here. Thus, there is hardly any horizontal movement of air.

It is believed that in ancient times ships with horses used to sail from Europe and the Middle-East to North America and islands of West Indies through this region.

While sailing through this region of calm the ships got stranded here for the lack of favourable wind. In such cases, the sailors used to throw their dead or dying horses in the sea to make the ships lighter and to conserve food and drinking water for themselves. Thus, the name ‘horse latitudes’ came into being.

Question 5. Write about the major causes of high pressure in the higher latitudes.
Answer:

Major Causes Of High Pressure In The Higher Latitudes:-

There are two well known high pressure belts which exists around the north and south Poles between 80°-90° north and south latitudes. Following are the causes for which high pressure belts have been formed around the poles

  1. The poles remain completely covered with snow. So, very low temperature (below freezing point) prevails throughout the year. Hence, high pressure prevails here.
  2. These regions receive very slanted sun rays. Thus, they experience extremely low temperatures, along with high pressure.
  3. The poles experience six months’ day and six months’ night continuously. This keeps the poles cold enough throughout the year, thus high pressure belts has develop here.
  4. The rate of evaporation is very low because of extreme low temperature and so the wind does not rise and instead, settles.
  5. As warm air rises from the sub-polar low pressure belts in both the hemispheres it sinks in the poles after being cooled. This contributes to the high atmospheric pressure in this region.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds High Pressure regions in higher latitude

 

Question 6. Explain the relationship between air pressure and altitude.
Answer:

Relationship Between Air Pressure And Altitude:-

There exists an inverse relationship between air pressure and altitude.

Air pressure is maximum near the surface of the earth and at sea level because about 99% of the air mass prevails within 32 km of height above the earth’s surface.

Therefore, air pressure is higher at lower levels than at the higher layers of the atmosphere. Moreover, air becomes lighter with an increase in altitude and this lapse rate is about 0. 1inch or 3.4mb for every 600 feet of ascent.

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WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Relationship between air pressure and altitude

 

Question 7. If you visit Sandakphu, you might face certain problems while climbing up the mountain. Do you know what kind of problems you might face?
Answer:

Problems While Climbing Up The Mountain Like Sandakphu:-

Sandakphu is the highest point in West Bengal. It lies at a height of about 3630 m above the sea level. When we go there for trekking, we might face the following problems-

  1. We might face difficulties in walking along the slopes.
  2. As we go higher, we might face breathing problems because
  3. With every 300m increase in height above sea level, pressure decreases by 34 mb. The air density decreases quickly and oxygen level falls sharply, thus causing problems in breathing.
  4. The air is denser near the surface of the earth, but as height increases, the air becomes thinner. Thus the amount of oxygen in the air becomes less.
  5. The difference between atmospheric pressure on the top of a mountain and the air pressure within the human body makes people breathe faster.

Chapter 4 Topic A Pressure Belts And Winds Short Answer Type Questions

Question 1. What is air pressure?
Answer:

Air Pressure:-

As the gravitational force of the earth pulls the air towards itself like all other materials, the weight of air exerts pressure on each and every material, even on our bodies. This weight of air is called air pressure or atmospheric pressure. It is an important element of weather and climate.

Question 2. Classify atmospheric pressure.
Answer:

Classification Atmospheric Pressure:-

Atmospheric pressure is observed to be either high or low, which actually indicates the amount of air molecules contained in the air.

If the air at a particular region contains a larger number of molecules, it is said to have high pressure and vice versa. So, air with higher pressure is denser, and air having low pressure is lighter.

Question 3. How many air pressure belts are there on earth and prepare a list including all of them.
Answer:

Types Of Air Pressure Belts Are There On Earth:-

The earth has different atmospheric pressure zones in different regions. These zones that surround the earth are called atmospheric or air pressure belts.

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There are seven pressure belts

  1. Equatorial low pressure belt.
  2. Tropical high pressure belt in the northern hemisphere around the Tropic of Cancer.
  3. Tropical high pressure belt in the southern hemisphere around the Tropic of Capricorn.
  4. Sub-polar low pressure belt in the northern hemisphere.
  5. Sub-polar low pressure belt in the southern hemisphere.
  6. Polar high pressure belt at the north pole.
  7. Polar high pressure belt at the south pole.

Question 4. Atmospheric pressure is not the same all over the earth- Why?
Answer:

Atmospheric pressure is not the same all over the earth:-

Atmospheric pressure depends on several factors such as rotation of the earth, temperature, altitude, water vapour content of the air, topography and distance from the sea of a particular place.

For example, the equatorial region has developed a low pressure belt while polar regions have high pressure belts. Air pressure may also vary at different places the in different times depending on available weight of air there and the temperature of the region.

Question 5. What are equatorial doldrums?
Answer:

Equatorial Doldrums:-

The region on either side of the equator (0°) between 5° north and south latitudes is the hottest zone on earth, where the wind always moves upward, thereby creating a vacuum. Also, no significant horizontal movement of air is prevalent here.

Thus, a region of calm called the equatorial doldrums prevails here. This region actually represents the zone of convergence of north-east and south-east trade winds.

Question 6. Does the equatorial belt of calm extend over the earth continuously?
Answer:

The Equatorial Belt Of Calm Extend Over The Earth Continuously:-

The difference in temperature and air pressure on land and water surfaces obstructs the continuity of the pressure belt that forms at the equator. It thus gets divided into smaller divisions known as pressure cells.

Equatorial belt of calm is divided into three cells

  1. The largest cell extends from the indian ocean to the pacific ocean
  2. Over the atlantic ocean
  3. Over the pacific ocean, in the west of south america.

Question 7. On which regions does air descend after deflecting from the Antarctic sub-polar belt?
Answer:

After rising from Antarctic sub-polar belt, air descends over two regions

  1. Polar region of southern hemisphere and
  2. Southern sub-tropical region.

Question 8. Mention the latitudinal extents of horse latitude and doldrums and point them out in the diagram.
Answer:

Latitudinal extents of horse latitude- 25° to 35° north and south latitudes. Latitudinal extents of doldrums-0° to 5° north and south latitudes.

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Horse latitude and doldrum

Question 9. With the help of a diagram, illustrate which pressure belts witness vertical and displacement of air and which pressure belts witness convergence of air masses.
Answer:

Vertical displacement of air occurs in equatorial low pressure belt and sub-polar low pressure belts. Convergence of air masses occur in the sub- tropical high pressure belts and polar high pressure belts.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Pressure belts on the earths surface

 

Question 10. Which one, between winter and rainy season, records less atmospheric pressure and why? 
Answer:

Water vapour is always lighter than air and so the lighter moisture-laden wind exerts less pressure than the dry wind.
For this, atmospheric pressure remains high in winter as the wind then is dry, cold and devoid of moisture.

On the other hand, the rainy season records maximum humidity and the lowest air pressure due to its very high moisture content.

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Question 11. Why cannot we feel the air pressure?
Answer:

We Cannot Feel The Air Pressure:-

We cannot feel the air pressure due to the following reason-Our body has air inside it, which exerts outward pressure that is equal to to the atmospheric pressure exerted on our body from the outside.

The air pressure in our body, lungs, ears and stomach is the same as the air pressure outside of our bodies. For this reason, we do not feel the atmospheric or air pressure.

Question 12. Why do mountaineers use oxygen cylinders?
Answer:

Mountaineers Use Oxygen Cylinders Because :-

As we move higher up a mountain, there is a decrease in temperature and air pressure approximately at the rate of 34 millibar for every 600 feet of ascent.

Air pressure being less here, air becomes thinner and its oxygen content decreases. So, carrying an oxygen cylinder is necessary for the mountaineers in order to breath properly.

Question 13. What is an isobar?
Answer:

Isobar:-

An isobar is an imaginary line drawn on a map or weather chart, joining all places having equal atmospheric pressure at sea level at a given time.

As we know that air pressure decreases at the rate of 34mb per 600 feet of ascent, the isobars have to be converted to sea level before preparing a weather chart or map.

Isobars are expressed in millibars. These lines are more crenulated in the northern hemisphere than southern hemisphere.

 

WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Isobar extending over India and her neighbouring countries

WBBSE Class 8 Geography Chapter 8 Question Answer

Chapter 4 Topic A Pressure Belts And Winds Multiple Choice Questions Choose The Correct Option

Question 1. The weight of air is called-

  1. Air pressure
  2. Air temperature
  3. Humidity
  4. Relative density

Answer: 1. Air pressure

Question 2. The total number of permanent pressure belts in the atmosphere is-

  1. Three
  2. Five
  3. Six
  4. Seven

Answer: 4. Seven

Question 3. Permanent low pressure belt in the atmosphere occurs in the-

  1. Equatorial region
  2. Sub-tropical regions
  3. Polar regions
  4. Desert regions

Answer: 1. Equatorial region

Question 4. Doldrums exist in the-

  1. Equatorial region
  2. Sub-polar region
  3. Polar region
  4. Desert region

Answer: 1. Equatorial region

Question 5. The regions between 25°-35° north and south latitudes are known as-

  1. Aequatorial low pressure belt
  2. Sub-polar low pressure belt
  3. Sub-tropical high pressure belt
  4. Polar high pressure belt

Answer: 3. Sub-tropical high pressure belt

Question 6. The high pressure belt/calm region. around the Tropic of Cancer is called-

  1. Horse latitudes
  2. Roaring forties
  3. Furious fifties
  4. Doldrums

Answer: 1. Horse latitudes

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 7. The tropical doldrums on the Atlantic Ocean is also called the-

  1. Roaring forties
  2. Doldrums
  3. Horse latitudes
  4. Equatorial belt of calm

Answer: 3. Horse latitudes

Question 8. Winds from the sub-polar belt of the southern hemisphere rise and move down to the-

  1. Antarctic region
  2. Equatorial region
  3. Arctic region
  4. Tropical region

Answer: 1. Antarctic region

Question 9. In comparison to the polar regions, the sub-polar regions of both the hemispheres record temperature which is-

  1. Very low
  2. Low
  3. High
  4. Same

Answer: 3. High

Question 10. Winds in both poles are-

  1. Heavy and cold in nature
  2. Warm and light in nature
  3. Cold and light in nature
  4. Heavy and warm in nature

Answer: 1. Heavy and cold in nature

Question 11. Which of the following regions has the highest air density?

  1. Equatorial region
  2. Polar regions
  3. Sub-polar regions
  4. Tropical regions

Answer: 2. Polar regions

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 12. The Antarctic region is dominated by-

  1. Both high and low pressure
  2. Nothing of the sort
  3. Low pressure
  4. High pressure

Answer: 4. High pressure

Question 13. Greenland is situated in the-

  1. Equatorial belt or region
  2. Tropical region
  3. Temperate zone
  4. Polar region

Answer: 4. Polar region

Question 14. The difference in isobars denotes-

  1. Air pressure gradient
  2. Deflection of air pressure
  3. Areas of high air pressure
  4. Areas of equal air pressure

Answer: 1. Air pressure gradient

Chapter 4 Topic A Pressure Belts And Winds Very Short Answer Type Questions Fill In The Blanks

Question 1. The equatorial region receives almost sun _______ rays throughout the year.
Answer: vertical

Question 2. The equatorial low pressure belt occurs between _______ and _______ both the hemispheres.
Answer: 0°,5°

Question 3. The _______ belt occurs between 5° north and south latitudes and _______ belts occur between 60°-70° north and south latitudes in both the hemispheres.
Answer: Equatorial, sub-polar

Question 4. An increase in air temperature causes a/an _______ in air pressure and a decrease in air temperature causes a/an in air pressure.
Answer: Decrease, Increase

Question 5. The regions lying between 25°-35° north and south latitudes are called _______.
Answer: Horse latitudes

Question 6. The maximum difference of atmospheric pressure occurs in the months of January and _______.
Answer: July

Question 7. The imaginary lines joining places with equal atmospheric pressure on a map are called _______.
Answer: Isobars

Question 8. The _______ hemisphere develops very definite air pressure cells.
Answer: Southern

Question 9. _______ is the instrument that is used to measure air pressure.
Answer: Barometer

Question 10. The Barometer was invented by _______ in 1643.
Answer: Torricelli

Question 11. The unit of measuring atmospheric pressure is
Answer: Millibar

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Write True Or False

Question 1. Centrifugal force is a result of the rotation of the earth.
Answer: True

Question 2. The region between 0° and 5° latitudes is known as the equatorial belt of calm or doldrums.
Answer: True

Question 3. The sub-tropical belts of calm occur between 10°-20° north and south latitudes.
Answer: False

Question 4. A wind vane records the velocity of the wind.
Answer: False

Question 5. Water vapour content/humidity and air pressure vary proportionately.
Answer: False

Question 6. The sun is the chief source of heat or temperature in the atmosphere.
Answer: True

Question 7. Polar regions record low atmospheric pressure.
Answer: False

Question 8. The wind in the equatorial region is hot, humid and light.
Answer: True

Question 9. The greater the difference in atmospheric pressure between a high pressure and a low pressure belt, the lower will be the velocity of the wind there.
Answer: False

Question 10. Descending air current prevails in the equatorial region.
Answer: False

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Match The Columns

1.WBBSE Solutions For Class 8 Geography Chapter 4 Topic A Pressure Belts And Winds Match the columns

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

 

Answer In One Or Two Words

Question 1. Name the different types of air pressure.
Answer:

  1. High pressure and
  2. low pressure.

Question 2. Name the type of pressure belt that has formed over the equatorial region.
Answer: Low-pressure belt.

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Question 3. Name two countries and oceans over which equatorial low-pressure belt is found.
Answer:

  1. Countries-Malaysia, Kenya.
  2. Oceans- Indian Ocean, Atlantic Ocean.

Question 4. What type of pressure belts are formed over the sub-tropical regions?
Answer: Low-pressure belts.

Question 5. Think and say whether high or low pressure is prevalent in the sub-polar belts.
Answer: Low-pressure belt.

Question 6. What kind of pressure belt is located over both poles?
Answer: High-pressure belt.

Question 7. Write down the names of two countries and two seas in the Arctic polar region.
Answer:

  1. Countries-Norway, Sweden.
  2. Seas-Barents Sea, Laptev Sea.

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