Class 7 Geography Lesson 5 Winds Questions and Answers | Maharashtra Board

 Class 7 Geography  Lesson 5: Winds

Exercise 

Q.1 Rewrite the following statements after choosing the correct option.

(1) When the air expands, it __________.

1. becomes solid
2. becomes thinner
3. gets lost
4. becomes humid

Answer: (b) becomes thinner

(2) From high air pressure regions, winds __________.

1. blow to regions of still higher pressure.
2. blow towards regions of cooler air.
3. blow towards regions of low air pressure.
4. remain still.

Answer: (c) blow towards regions of low air pressure.

(3) In the northern hemisphere, winds blowing towards the equator __________ due to the rotation of the earth.

1. turn to the south
2. turn to the east
3. turn to the west
4. turn to the north

Answer: (b) turn to the east

(4) The direction of seasonal winds blowing over the Indian subcontinent during winter is from the __________.

1. south-east to north-west.
2. south-west towards north-east.
3. north-east to south-west.
4. north-west to south-east.

Answer: (d) north-west to south-east.

(5) The Roaring Forties in the southern hemisphere __________.

1. blow towards the equator.
2. blow in the areas around 40° S parallel.
3. blow from the subpolar region of low pressure.
4. blow around 40° N parallel.

Answer: (b) blow in the areas around 40° S parallel.

Q.2 Identify the type of winds from the description given below.

(1) These winds from the south-west bring rains to the Indian subcontinent. During June to September, India gets rains. After this period, these winds retreat.

Answer: South-West Monsoon Winds

(2) These winds, blowing from the north pole region towards 60° N parallel, cause cold wave conditions in extensive areas covering North America, Europe and Russia.

Answer: Polar Easterlies

(3) Hilltops get heated quickly during the day. The air in this part becomes hot, light and starts ascending. Hence, a low-pressure area forms in this region. At the same time, the air at the foothills becomes cooler, and that area experiences high pressure. Air in that area blows towards low pressure.

Answer: Valley Breeze

Q.3. Given below are the values of air pressure in millibars. Using the same, draw diagrams to show a cyclone and an anticyclone.

• 990, 994, 996, 1000
• 1030, 1020, 1010, 1000

Q.4. State one reason why:

(1) A belt of calm exists near the equator.

Answer: The air near the equator gets strongly heated, becomes light and rises vertically. Hence, the surface winds are very weak and a belt of calm exists.

(2) The winds coming from the north-west in the southern hemisphere have greater velocities than the winds coming from the south-west in the northern hemisphere.

Answer: The Southern Hemisphere has more ocean and less land. Therefore, the winds face less friction and obstacles and have greater velocity.

(3) The monsoon winds in the summer come from the sea but the retreating monsoon winds in winter come from land.

Answer: Land and water heat and cool at different rates. Therefore, the pressure conditions reverse in summer and winter, changing the direction of the monsoon winds.

Q5. Complete the chart

Q.6. Answer in short:

(1) Why is the air pressure high in polar areas in both the hemispheres?
Answer: The air at the poles is very cold, dense and heavy. It sinks towards the Earth's surface and creates high pressure.

(2) What effect does the rotation of the earth have on the winds?
Answer: The rotation of the Earth deflects the winds from their original direction. They turn right in the Northern Hemisphere and left in the Southern Hemisphere.

(3) Why do the cyclonic winds blow in a circular manner?
Answer: Winds move towards the low-pressure centre of a cyclone. The rotation of the Earth deflects these winds, making them blow in a circular or spiral manner.

(4) State the reasons that lead to the formation of cyclones and describe the effects of cyclones.
Answer: Cyclones form over warm seas due to a low-pressure area. Warm, moist air rises and condensation releases energy, strengthening the cyclone.
Effects: Cyclones bring strong winds, heavy rainfall, floods and storm surges. They can damage houses, crops, trees and communication systems.

Can You Tell? – Question 

Q1. See outside the window of your classroom. Which objects are moving? Which are still?

Answer: Trees, leaves, birds, vehicles and people moving outside the classroom are moving objects. Buildings, electric poles and other fixed objects are still.

Q2. Which objects are moving on their own?

Answer: People, animals and birds can move on their own.

Q3. Which objects are not moving on their own? Why?

Answer: Vehicles, leaves, branches and other objects do not move on their own. They need an external force, such as a person pushing or pulling them or wind blowing against them.

Q4. Why do we feel the wind but cannot see it?

Answer: Wind is moving air. We cannot see air, but we can feel its movement when it blows against our body.

Observe Fig. 5.3 and Answer

Q1. Which are the winds in the Northern Hemisphere that blow from the mid-latitudinal high pressure belt to the equatorial low pressure belt?

Answer: The North-East Trade Winds blow from the mid-latitudinal high pressure belt towards the equatorial low pressure belt in the Northern Hemisphere.

Q2. What is the direction of the Westerlies in the Southern Hemisphere?

Answer: In the Southern Hemisphere, the Westerlies blow from the north-west towards the south-east.

Q3. Which planetary winds blow from the mid-latitudinal high pressure belts to the subpolar low pressure belts in the Northern Hemisphere?

Answer: The Westerlies blow from the mid-latitudinal high pressure belt towards the subpolar low pressure belt in the Northern Hemisphere.

Q4. Why is the direction of polar winds not the same in both the hemispheres?

Answer: The direction of polar winds is different in the two hemispheres because of the Coriolis effect caused by the rotation of the Earth. The winds are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Q5. Name the winds that blow in the Southern Hemisphere.

Answer: The main planetary winds that blow in the Southern Hemisphere are:

• South-East Trade Winds
• Westerlies
• Polar Easterlies

Q6. In which direction do the Easterlies blow in the Northern and Southern Hemispheres?

Answer:

• In the Northern Hemisphere, the Easterlies blow from north-east to south-west.
• In the Southern Hemisphere, the Easterlies blow from south-east to north-west.

Can You Tell? – Sea Breeze and Land Breeze

Q1. Why do the breezes blow from the sea to the land during the day?

Answer: During the day, land gets heated faster than the sea. The air over the land becomes warm and rises, creating a low-pressure area. The cooler air over the sea moves towards the land to replace the rising warm air. This breeze is called a sea breeze.

Q2. When do the winds blow from the land to the sea?

Answer: At night, the land cools faster than the sea. The air over the land becomes cooler and creates a high-pressure area. The warmer air over the sea rises, creating low pressure. Therefore, cool air moves from the land towards the sea. This is called a land breeze.

Q3. Describe the winds shown in Fig. 5.5a.

Answer: Fig. 5.5a shows a sea breeze. During the day, the land gets heated faster than the sea. Warm air over the land rises and creates low pressure. Cooler air from the sea moves towards the land. Thus, the wind blows from the sea towards the land.

Q4. Compare Fig. 5.5a and Fig. 5.5b with reference to temperature conditions, air pressure and winds.

Fig. 5.5a – Sea Breeze	Fig. 5.5b – Land Breeze
It occurs during the day.	It occurs at night.
Land is hotter than the sea.	Land is cooler than the sea.
Low pressure develops over the land.	High pressure develops over the land.
Wind blows from the sea to the land.	Wind blows from the land to the sea.

Q5. Which winds are called sea breezes and which are called land breezes? Why?

Answer: The cool winds that blow from the sea towards the land during the day are called sea breezes. The cool winds that blow from the land towards the sea at night are called land breezes. They are named according to the direction in which they blow.

Q6. In which part of India are the land and sea breezes experienced?

Answer: Land and sea breezes are experienced mainly in the coastal parts of India, along the western and eastern coastal areas.

Q7. Do you experience sea and land breezes in your area?

Answer: People living in coastal areas experience sea and land breezes. People living far from the coast generally do not experience these breezes clearly.