NCERT Solutions for Class 7 Social Science Geography Chapter 4 Air

Air Class 7 Questions and Answers Geography Chapter 4

Class 7 Geography Chapter 4 NCERT Textbook Questions and Answers

Question 1.
Answer the following questions :

(i) What is the atmosphere?
Answer:
A blanket of air surrounding the earth is called atmosphere.

(ii) Which two gases make the bulk of the atmosphere?
Answer:
Nitrogen and oxygen are the two gases which make the bulk of the atmosphere.

(iii) Which gas creates green house effect in atmosphere?
Answer:
Carbon dioxide creates a green house effect in the atmosphere by trapping the heat radiated from the earth.

(iv) What is weather?
Answer:
The hour-to-hour, day-to-day condition of the atmosphere is called weather.

(v) Name three types of rainfall.
Answer:
The three types of rainfall are“
Cyclonic rainfall
Relief (Orographic) rainfall
Convectional rainfall

(vi) What is air pressure?
Answer:
The pressure exerted by the weight of the air on the earth’s surface is called air pressure.

Question 2.
Tick the correct answer :
(i) Which of the following gases protects us from harmful sun rays?
(a) Carbon dioxide
(b) Nitrozen
(c) Ozone
Answer:
(c) Ozone.

(ii) The most important layer of the atmosphere is-
(a) Troposphere
(b) Thermosphere
(c) Mesosphere
Answer:
(a) Troposphere.

(iii) Which of the filling layers of the atmosphere is free from clouds?
(a) Temperature
(b) Air pressure
(c) Stratosphere
Answer:
(c) Stratosphere.

(iv) As we go up the layers of the atmosphere, the pressure.
(a) increases
(b) decreases
(c) remain the same
Answer:
(b) decreases.

(v) When precipitation comes down to the earth in the liquid form, it is called
(a) cloud
(b) rain
(c) snow
Answer:
(b) rain.

Question 3.
Match the following-

(i) Trade winds (a) Seasonal wind
(ii) Loo (b) horizontal movement of air
(iii) Monsoon (c) permanent wind
(iv) Wind (d) local wind

Answer:

(i) Trade winds (c) permanent wind
(ii) Loo (d) local wind
(iii) Monsoon (a) Seasonal wind
(iv) Wind (b) horizontal movement of air

Question 4.
Give reasons-
(a) Wet clothes take longer time to dry on a humid day?
(b) Amount of insolation decreases from equator towards the poles
Answer:
(a) When the air is full of water vapour we call it a humid day. On a humid day, the capacity of the air to hold more water vapours decreases. Hence, wet clothes take longer time to dry on a humid day.

(b) The equator is near the sun than the poles. The sun rays directly fall on the equator while the sun rays are slanting towards the poles. Hence the amount of insolation decreases from the equator towards the poles.

Question 5.
For fun-
(a) Solve this crossword puzzle with the help of given clues?

NCERT Solutions for Class 7 Social Science Geography Chapter 4 Air 1

Across Down
6. An Indian tree having extraordinary quality of providing oxygen round the clock 1. Amount of water vapour in air
8. Gas present in atmosphere occupying only 0.03% by volume 2. Condensation of water vapours around dust particles in atmosphere
11. Outermost layer of atmosphere 3. Example of local wind blowing in summer in northern India
12. Mixture of many gases 4. Short term changes in atmosphere
14. Life giving gas 5. Precipitation in liquid form
15. Air in motion 7. Blanket of air around the earth
16. An Indian tree valued highly for medicinal properties 9. Instrument to measure pressure
18. Gas protecting us from harmful sunrays 10. Incoming solar radiation
19. Low pressure area 13. Reduces visibility in winters
17. It is time when sun is overhead

Answer:
Across :
6. Peepal
8. Carbon dioxide
11. Exosphere
12. Air
14. Oxygen
15. Wind
16. Neem
18. Ozone
19. Cyclone.

Down :
1. Humidity
2. Cloud
3. Loo
4. Weather
5. Rain
7. Atmosphere
9. Barometer
10. Insolation
13. Fog
17. Noon.

(ii) Make a weather calendar for one week. Use pictures or symbols to show different types of weather. You can use more than one symbol in a day, if the weather changes. For example, the sun comes out when rain stops. An example is given below-
NCERT Solutions for Class 7 Social Science Geography Chapter 4 Air 2
Answer:
NCERT Solutions for Class 7 Social Science Geography Chapter 4 Air 3

NCERT Solutions for Class 7 Social Science

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