UPSC CSE Prelims
Question 77
With reference to the Earth's atmosphere, which one of the following statements is correct?
View correct answer and explanation
Correct answer: C
Correct Option: C (Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.)
Explanation: Water vapour strongly absorbs terrestrial and incoming near-infrared radiation in lower atmospheric layers through molecular absorption bands.
Option-wise Analysis:
A. Incorrect-Equator-to-pole insolation differences do not support this blanket tenfold ratio.
B. Incorrect-Incoming solar radiation is largely visible/shortwave; infrared is not roughly two-thirds as stated.
C. Correct-water vapour absorbs infrared strongly, particularly in the lower atmosphere.
D. Incorrect-Infrared has longer wavelengths than visible light, so it lies outside the visible spectrum.