2023 GS Paper I, all questions
UPSC Prelims 2023 · GS Paper I
Question 62: Geography
With reference to the Earth's atmosphere, which one of the following statements is correct?
aThe total amount of insolation received at the equator is roughly about 10 times of that received at the poles.
bInfrared rays constitute roughly two-thirds of insolation.
cInfrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
dInfrared waves are a part of visible spectrum of electromagnetic waves of solar radiation.
AnswerUPSC’s answer is (c).
Infrared waves are absorbed largely by water vapour (and carbon dioxide) concentrated in the lower atmosphere, which underlies the greenhouse effect, so (c) is correct. Insolation at the equator is only about two to three times that at the poles, not ten times. Infrared makes up about half of insolation, not two-thirds, and it lies outside the visible spectrum.
Why each option is right or wrong
- (a) Equatorial insolation is only a few times, not about ten times, that at the poles.
- (b) Infrared is roughly half of insolation, not two-thirds.
- (c) Correct: water vapour in the lower atmosphere absorbs infrared waves.
- (d) Infrared lies beyond the red end of the visible spectrum.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2023, General Studies Paper I, Series A. The paper on upsc.gov.in.