With reference to the Earth's atmosphere, which one of the following statements is correct?
A
The total amount of insolation received at the equator is roughly about 10 times of that received at the poles.
B
Infrared rays constitute roughly two-thirds of insolation.
C
Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
Correct Answer
D
Infrared waves are a part of visible spectrum of electromagnetic waves of solar radiation.
Explanation
Option (C) is correct because water vapour, which is heavily concentrated in the lower atmosphere (troposphere), acts as a significant absorber of both incoming solar infrared radiation and outgoing terrestrial long-wave radiation. Option (B) is the most tempting error, but it is incorrect because infrared radiation constitutes approximately 45–50% of total insolation, not two-thirds. The core concept being tested is the composition of solar radiation and the selective absorption properties of atmospheric gases within the Earth's energy budget.
Climatology / Atmospheric ScienceEarth's Atmosphere and Solar Radiation (Insolation, Infrared)Earth's atmosphereinsolationequatorpolesinfrared rayswater vapourlower atmospherevisible spectrumelectromagnetic wavessolar radiationgreenhouse effect