Air | Geography VII | Class 7th | Questions and Answers

 

JANDKNCERT | Social Science | Our Environment

Air | Geography VII | Class 7th | Questions and Answers

 

Chapter 4: Air

1. Answer the following questions

Question (i): What is the atmosphere?
Answer: The atmosphere is the blanket of air that surrounds the Earth. It provides us with the air we breathe and protects us from harmful rays of the sun.

Question (ii): Which two gases make the bulk of the atmosphere?
Answer: Nitrogen (78%) and Oxygen (21%) make up the bulk of the atmosphere.

Question (iii): Which gas creates a greenhouse effect in the atmosphere?
Answer: Carbon dioxide creates a greenhouse effect in the atmosphere by trapping heat.

Question (iv): What is the weather?
Answer: Weather is the day-to-day condition of the atmosphere, including temperature, rainfall, wind, and humidity at a particular place and time.

Question (v): Name three types of rainfall.
Answer:
(i) Convectional rainfall
(ii) Orographic rainfall
(iii) Cyclonic rainfall

Question (vi): What is air pressure?
Answer: Air pressure is the force exerted by the weight of air on the Earth's surface. It is highest at sea level and decreases with height.

2. Tick the correct answer

Question (i): Which of the following gases protects us from harmful sun rays?
Answer: (b) Ozone

Question (ii): The most important layer of the atmosphere is
Answer: (c) Troposphere

Question (iii): Which of the following layers of the atmosphere is free from clouds?
Answer: (b) Stratosphere

Question (iv): As we go up the layers of the atmosphere, the pressure
Answer: (a) Decreases

Question (v): When precipitation comes down to the Earth in the liquid form, it is called
Answer: (b) Rain

3. Match the following

Question	Answer
(i) Trade Winds	(d) Permanent winds
(ii) Loo	(c) Hot and dry local wind of summer
(iii) Monsoon	(b) Seasonal wind
(iv) Wind vane	(a) Shows wind direction
(v) Barometer	(e) Measures air pressure

4. Give reasons

Question (i): Wet clothes take longer time to dry on a humid day.
Answer: On a humid day, the air already contains a lot of moisture, so it absorbs less water from wet clothes, making them dry slower.

Question (ii): Amount of insolation decreases from equator towards poles.
Answer: The equator receives direct sunlight due to its position, while the poles receive slanting rays, reducing the amount of insolation.