NCERT Solutions for Class 7 Social Science Geography Chapter 4 Air

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Air NCERT Solutions for Class 7 Social Science Geography Chapter 4

Class 7 Geography Chapter 4 Air InText Questions and Answers

Activity

Text Book Page No. 23

Question 1.
For ten days note down weather report from a local newspaper and observe the changes occurring in the weather.
Answer:
Students do themselves.

Class 7 Geography Chapter 4 Air Exercise Questions and Answers

Question 1.
Answer the following questions.
(1) What is atmosphere ?
Answer:
A huge blanket of air by which our earth is surrounded called atmosphere.

(2) Which two gases make the bulk of atmosphere ?
Answer:
(a) Nitrogen
(b) Oxygen

(3) Which gas creates green house effect in atmosphere ?
Answer:
Carbon dioxide

(4) What is weather ?
Answer:
Weather is hour-to-hour, day to day condition of the atmosphere.

(5) Name three types of rainfall.
Answer:

1. The convectional rainfall
2. The orographic rainfall and
3. The cyclonic rainfall

(6) What is air pressure ?
Answer:
Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface. .

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

(2) The most important layer of atmosphere is
(a) Troposphere
(b) Thermosphere
(c) Mesosphere
Answer:
(a) Troposphere

(3) Which of the following layers of atmosphere is free from clouds ?
(a) Troposphere
(b) Stratosphere
(c) Mesosphere
Answer:
(b) Stratosphere

(4) As we go up the layers of the atmosphere, the pressure
(a) Increases
(b) Decreases
(c) Remain same
Answer:
(b) Decreases

(5) 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 :

Trade	Seasonal wind
winds Loo	Horizontal movement of air
Monsoon	Permanent wind
Wind	Local wind

Answer:

Trade	Permanent wind
winds Loo	Local wind
Monsoon	Seasonal wind
Wind	The horizontal movement of air

Give reasons

Question 4.
(1) Wet clothes take a longer time to dry on a humid day?
Answer:
On a humid day, the air is full of water vapour. Hence, evaporation is very slow. This is the reason why wet clothes take a longer time to dry on a humid day.

(2) Amount of insolation decreases from the equator towards poles?
Answer:
Insolation comes through vertical rays on the equator. Thus, it covers up less space but we feel more heat there when it goes up from the equator towards the poles, the sun rays become slanting. Needless to say that slanting rays come on the earth covering longer distances. Although these slanting rays heat up more space, the degree of hotness is felt less. This is the reason why the amount of insolation decreases from the equator towards the poles.

For Fun

Question 5.
(1) Solve this crossword puzzle with the help of given clues (on page 28) :
Answer:

(2) 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 the rain stops. An example is given below:
Answer: