Air

NCERT Solution

Question 1: Wet clothes take longer time to dry on a humid day. Why?

Answer: Humidity level is very high on a humid day, i.e. plenty of water vapour is present in air. In this condition, air is unable to take up more water vapour. Due to this, clothes take longer to dry on a humid day.

Question 2: Amount of insolation decreases from equator towards poles. Why?

Answer: Sunlight falls almost vertically on the equator, while it falls at slanting angle on the poles. Due to this, amount of insolation decreases from equator towards poles.


Answer the following questions:

Question 3: What is atmosphere?

Answer: It is the huge blanket of air that surrounds the earth.

Question 4: Which two gases make the bulk of the atmosphere?

Answer: Nitrogen and oxygen

Question 5: Which gas creates green house effect in the atmosphere?

Answer: Carbon dioxide

Question 6: What is weather?

Answer: It is the hour to hour, day to day condition of the atmosphere.

Question 7: Name three types of rainfall?

Answer: Convectional rainfall, orographic rainfall and the cyclonic rainfall.

Question 8: What is air pressure?

Answer: The pressure exerted by the weight of air on the earth’s surface.


Multiple Choice Questions:

Question 1: Which of the following gases protects us from harmful sun vays?

  1. Carbon dioxide
  2. Nitrogen
  3. Ozone

Answer: (c) Ozone

Question 2: The most important layer of the atmosphere is

  1. Troposphere
  2. Thermosphere
  3. Mesosphere

Answer: (a) Troposphere

Question 3: Which of the following layers of the atmosphere is free from clouds?

  1. Troposphere
  2. Stratosphere
  3. Mesosphere

Answer: (b) Stratosphere

Question 4: As we go up the layers of the atmosphere, the pressure

  1. Increases
  2. Decreases
  3. Remains the same

Answer: (b) Decreases

Question 5: When precipitation comes down to the earth in the liquid form, it is called

  1. Cloud
  2. Rain
  3. Snow

Answer: (b) Rain


Match the following:

Column IColumn II
(i) Trade wind(a) Incoming solar energy
(ii) Loo(b) Seasonal wind
(iii) Monsoon(c) Horizontal movement of air
(iv) Wind(d) Layer of ozone gas
(e) Permanent wind
(f) Local wind

Answer: (i) - e, (ii) - f, (iii) - b, (iv) - c,



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