- A. (a) The total amount of insolation received at the equator is roughly about 10 times of that received at the poles.
- B. (b) Infrared rays constitute roughly two- thirds of insolation.
- C. (c) Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
- D. (d) Infrared waves are a part of visible spectrum of electromagnetic waves of solar radiation.
Answer: C
Explanation
Statement (a) is incorrect; insolation at the equator is roughly 2-3 times, not 10 times, that at the poles. Statement (b) is incorrect; insolation (incoming solar radiation) is primarily shortwave radiation, including visible light and ultraviolet, with infrared constituting a smaller portion. Longwave radiation emitted by Earth is mostly infrared. Statement (d) is incorrect; infrared waves have longer wavelengths than visible light and are not part of the visible spectrum. Statement (c) is correct; water vapor is a potent greenhouse gas and strongly absorbs infrared radiation, particularly in the lower atmosphere (troposphere), contributing significantly to the greenhouse effect. This question tests fundamental concepts of climatology and atmospheric science, a core part of UPSC Geography.