# NCERT Solutions for Class 7 Geography Chapter-4

Aug 17, 2023, 16:45 IST

### About NCERT Solutions for Class 7 Geography Chapter 4- Air

This page consist of NCERT Solutions for Class 7 Geography Chapter 4- Air all questions asked in Exercise are solved with adequate details. Do solve NCERT maths and science with the help of NCERT Solutions for class 7 Maths and NCERT solutions for class 7 Science prepared by PhysicsWallah.

Chapter 4

### Air

Question1.

(i) What is atmosphere?

Answer. A huge blanket of air by which our earth is surrounded is called atmosphere.

The atmosphere have following layers :

(a) Troposphere.

(b)Stratosphere

(c) Mesosphere

(d) Thermosphere

(e) Exosphere

Out of these atmospheric layers, Troposphere is the most important layer of the atmosphere, which directly support life on this planet.

(ii) Which two gases make the bulk of atmosphere?

(b) Oxygen.

(iii) Which gas creates green house effect in atmosphere?

(iv) What is weather?

Answer. Weather is hour-to-hour, day to day conditions of the atmosphere.

(v) Name three types of rainfall?

(ii) The Orographic rainfall. and

(iii) The cyclonic rainfall.

(vi)  What is air pressure?

Answer. Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface.

(i) Which of the following gases protects us from harmful sun rays?

(a) Carbon dioxide.

(b) Nitrogen.

(c) Ozone.

(ii) The most important layer of the atmosphere is.

(a) Troposphere.

(b)Thermosphere.

(c) Mesosphere

(iii) Which of the following layers of atmosphere free from clouds?

(a) Troposphere.

(b) Stratosphere.

(c) Mesosphere

(iv) As we go up the layers of the atmosphere, the pressure.

(a) Increases.

(b) Decreases.

(c) Remain same.

(v)When precipitation comes down to the earth liquid form, it is called:

(a) cloud.

(b) Rain.

(c) Snow.

Question3. Match the following:

2 Loo.                           (b) Horizontal  movement of  air.

3 Monsoon.                  (c) Permanent  wind

4 Wind.                        (d) Local  wind

1 Trades winds.            (c) Permanent wind.

2 Loo.                           (d)  Local wind .

3 Monsoon.                  (a)  Seasonal.

4 Wind.                         (b)  Horizontal movement of air.

Question4. Give reasons.

(i) Wet clothes take longer time to dry on a humid day?

Answer. Because sun rays fall vertical on the equator while slanting on the poles.

(ii). Amount of isolation decreases from equator towards poles?

Answer. Because on a humid day, there is more water in air than a sunny day. So, air can soak less weather from wet clothes i.e., rate of evaporation decreases.

Question5. For fun.

(i). Solve this crossword puzzle with the help of given clues:

### Across

6. An Indian tree having extraordinary quality of providing oxygen round the clock

8. Gas present in atmosphere occupying only 0.03% by volume

11. Outermost layer of atmosphere

12. Mixture of many gases

14. Life giving gas

15. Air in motion

16. An Indian tree valued highly for medicinal properties

18. Gas protecting us from harmful sunrays

19. Low pressure area

### Down

1. Amount of water vapor in air

2. Condensation of water vapors around

dust particles in atmosphere

3. Example of local wind blowing in summer in northern India

4. Short term changes in atmosphere

5. Precipitation in liquid form

7. Blanket of air around the earth

9. Instrument to measure pressure