I. Choose the correct answer

Question 1.
Atmosphere contains
(a) oxygen
(b) nitrogen
(c) dust particles
(d) all of them

Answer

Answer: (d) all of them

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Question 2.
Which gas is essential for breathing?
(a) nitrogen
(b) oxygen
(c) carbon dioxide
(d) none of these

Answer

Answer: (b) oxygen

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Question 3.
What is the percentage of air in the atmosphere?
(a) 32
(b) 99
(c) 0.1
(d) 21

Answer

Answer: (b) 99

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Question 4.
At what height will oxygen be almost in negligible quantity?
(a) 120 km.
(b) 90 km.
(c) 18 km.
(d) 60 km.

Answer

Answer: (a) 120 km.

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Question 5.
What is the % of nitrogen in the atmosphere?
(a) 20.95%
(b) 78.08%
(c) 20%
(d) 80%

Answer

Answer: (b) 78.08%.

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Question 6.
Which gas is present in large amount in the atmosphere?
(a) oxygen
(b) hydrogen
(c) nitrogen
(d) carbon dioxide

Answer

Answer: (c) nitrogen.

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Question 7.
Name the gas which is useful for plants
(a) oxygen
(b) carbon dioxide
(c) argon
(d) hydrogen

Answer

Answer: (b) carbon dioxide.

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Question 8.
Which gas is found as a trace in the atmosphere?
(a) oxygen
(b) nitrogen
(c) carbon dioxide
(d) xenon

Answer

Answer: (d) xenon.

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Question 9.
What percentage of carbon dioxide is found in air?
(a) 0.036%
(b) 0.93%
(c) 0.002%
(d) 0,3%

Answer

Answer: (a) 0.036%.

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Question 10.
What percentage of oxygen is found in the air?
(a) 20.95
(b) 21.95
(c) 78.08
(d) 80.08

Answer

Answer: (a) 20.95.

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Question 11.
Which gas acts as a filter and protects us from the ultra violet rays?
(a) oxygen
(b) nitrogen
(c) ozone
(d) carbon dioxide

Answer

Answer: (c) ozone.

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Question 12.
Which layer of the atmosphere is useful for various biological activities?
(a) stratosphere
(b) troposphere
(c) ionosphere
(d) none of these

Answer

Answer: (b) troposphere.

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Question 13.
Which one is the variable gas in the atmosphere?
(a) carbon dioxide
(b) water vapour
(c) dust particles
(d) smoke

Answer

Answer: (b) water vapour.

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Question 14.
Which layer of the atmosphere is free from water vapours and clouds?
(a) troposphere
(b) stratosphere
(c) mesosphere
(d) exosphere

Answer

Answer: (b) stratosphere.

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Question 15.
The zone separating troposphere from stratosphere is known as
(a) tropopause
(b) stratopause
(c) mesopause
(d) none of these

Answer

Answer: (a) tropopause.

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Question 16.
Upto what height does the stratosphere extend?
(a) 60 km.
(b) 80 km.
(c) 50 km.
(d) 120 km.

Answer

Answer: (c) 50 km.

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Question 17.
The mesosphere lies above the
(a) troposphere
(b) stratosphere
(c) ionosphere
(d) exosphere

Answer

Answer: (b) stratosphere.

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Question 18.
The upper limit of mesosphere is known as
(a) tropopause
(b) mesopause
(c) stratopause
(d) exopause

Answer

Answer: (b) mesopause.

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Question 19.
Ionosphere is located between
(a) 80 and 400 km.
(b) 80 and 500 km.
(c) 40 and 400 km.
(d) 40 and 200 km.

Answer

Answer: (a) 80 and 400 km.

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Question 20.
Radio waves are transmitted from which layer?
(a) mesosphere
(b) exosphere
(c) ionosphere
(d) none of These

Answer

Answer: (c) ionosphere.

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Question 21.
Chief elements of the atmosphere are
(a) wind
(b) temperature
(c) pressure
(d) all of them

Answer

Answer: (d) all of them.

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Question 22.
Atmospheric elements are controlled by
(a) latitude
(b) altitude
(c) land
(d) all of them

Answer

Answer: (d) all of them.

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II. Fill up the blanks with suitable words

Question 1.
The …………… is essential for various organisms.

Answer

Answer: air

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Question 2.
Atmosphere is a mixture of different ……………. and it ………….. the earth all round.

Answer

Answer: gases, envelopes

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Question 3.
The air is ……………, …………… and ……………

Answer

Answer: colourless, odourless, tasteless

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Question 4.
Carbon dioxide and water vapour are not found starting from …………….. and above.

Answer

Answer: 90 km.

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Question 5.
Carbon dioxide is largely responsible for the …………….. effect.

Answer

Answer: green house

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Question 6.
Ozone acts as a ……………. and …………….. the ……………… rays.

Answer

Answer: filter, absorbs, ultraviolet

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Question 7.
……………… also decreases front the equator towards the poles.

Answer

Answer: Water vapour

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Question 8.
Dust particles are concentrated in the ……………… of the atmosphere.

Answer

Answer: lower layer

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Question 9.
The column of atmosphere is divided into …………. different layers depending upon temperature conditions.

Answer

Answer: five

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Question 10.
Radio waves are transmitted from the …………….

Answer

Answer: Ionosphere

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