EVENTS CONVENT HIGH SCHOOL
08/10/2021 CLASS-7 SESSION 2021-22
SUBJECT :SOCIAL STUDIES (GEOGRAPHY)
chapter-4
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Question 1.Answer the following questions briefly.
(i) What is atmosphere?
(ii) Which two gases make the bulk of the atmosphere?
(iii) Which gas creates greenhouse effect in the atmosphere?
(iv) What is weather?
(v) Name three types of rainfall
(vi) What is air pressure?
Answer:
(i) Atmosphere is a thin blanket of air that surrounds the earth. It protects us from the harmful rays of the sun. It consists of several gases in which nitrogen and oxygen occupy the major portion.
(ii) Nirtrogen (78%) and oxygen (21%) make the bulk of the atmosphere.
(iii) Carbon dioxide creates a greenhouse effect in the atmosphere.
(iv) Weather is the hour-to-hour, day-to-day condition of the atmosphere.
(v)
- Convectional rainfall
- Orographic rainfall
- Cyclonic rainfall.
(vi) The pressure exerted by the weight of air on the earth’s surface is known as air pressure.
Question 2. Tick the correct answer:
(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 the atmosphere is free from clouds?
(a) Trosphere (b) Stratosphere
(c) Mesosphere.
(iv) As we go up the layers of the atmosphere, the pressure
(a) Increases (b) Decreases
(c) Ramains the same.
(v) When precipitation comes down to the earth in the liquid form, it is called
(a) Cloud (b) Rain
(c) Snow.
Answer: (i)—(c), (ii)—(a), (iii)—(b), (iv)—(b), (v)—(b).
Question 4.
Give reasons:
- Wet clothes take longer time to dry on a humid day.
- Amount of insolation decreases from equator torwards poles?
Answer:
- As the air gets warmer its capacity to hold moisture, increases. Therefore it becomes more and more humid. On such days water from clothes or sweat from our body does not evaporate easily. Thus wet clothes take a longer time to dry.
- On the equator, insolation comes through vertical rays.
- It covers up less space. Hence heat is felt more.
- From the equator, it goes on coming through slanting rays. Slanting rays come on the earth passing longer distances through the atmosphere. They heat up more space. Hence there is less heat on a point of space.
