2022 GS Paper I, all questions

UPSC Prelims 2022 · GS Paper I

Question 81: Geography

Consider the following statements :

  1. 1.High clouds primarily reflect solar radiation and cool the surface of the Earth.
  2. 2.Low clouds have a high absorption of infrared radiation emanating from the Earth’s surface and thus cause warming effect.

Which of the statements given above is/are correct ?

a1 only
b2 only
cBoth 1 and 2
dNeither 1 nor 2

AnswerUPSC’s answer is (d).

The effect of clouds depends on height. High, thin clouds such as cirrus let most sunlight through but trap outgoing infrared radiation from the Earth, so they warm the surface. Low, thick clouds such as stratus reflect a large share of incoming sunlight, so they cool it. Both statements swap these roles, so neither is correct.

  • 1. High clouds mostly trap outgoing infrared and warm the surface.
  • 2. Low clouds mostly reflect sunlight and cool the surface.

How you could have got this

  1. If you were sure statement 1 is not correct, (a) and (c) go: each of them includes 1.

    What you needed to know: High clouds mostly trap outgoing infrared and warm the surface.

  2. Then, if you were sure statement 2 is not correct, (b) goes: it includes 2.

    What you needed to know: Low clouds mostly reflect sunlight and cool the surface.

Only (d) is left. This one needs every statement.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong
  • (a) Wrong. High clouds mainly warm by trapping infrared, not cool by reflecting.
  • (b) Wrong. Low clouds mainly cool by reflecting sunlight.
  • (c) Wrong. Both statements reverse the roles of high and low clouds.
  • (d) Correct. Both statements are the wrong way round.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2022, General Studies Paper I, Series A. The paper on upsc.gov.in.