With reference to the Earth's atmosphere, which one of the following statements is correct?

Question

Question

This question was previously asked in

UPSC Civil Services Prelims 2023: General Studies (SET - A - Held on 28 May)

The total amount of insolation received at the equator is roughly about 10 times of that received at the poles.
Infrared rays constitute roughly two-thirds of insolation.
Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
Infrared waves are a part of visible spectrum of electromagnetic waves of solar radiation.

Answer 1

The correct answer is Option 3

Key Points

Infrared Waves and Water Vapour:
- Infrared waves are largely absorbed by water vapour concentrated in the lower atmosphere.
- Water vapour acts as a greenhouse gas, absorbing infrared radiation emitted by the Earth's surface, playing a crucial role in regulating the Earth's temperature.
- Hence, Option 3 is correct.
Equator and Poles Insolation:
- Although the equator receives more direct sunlight than the poles, the difference in the total amount of insolation is not as extreme as ten times.
- The actual difference is much smaller due to the Earth's curvature and the distribution of solar energy.
- Hence, Option 1 is incorrect.
Proportion of Infrared Rays in Insolation:
- While infrared rays make up a portion of solar radiation, they do not constitute two-thirds of the insolation.
- Insolation consists of various wavelengths, including visible light, ultraviolet rays, and infrared rays.
- Hence, Option 2 is incorrect.
Infrared Waves and the Visible Spectrum:
- Infrared waves have longer wavelengths than visible light and are not part of the visible spectrum.
- They fall outside the range of light visible to the human eye.
- Hence, Option 4 is incorrect.