Question

Methane is a greenhouse gas because

• A. it absorbs longer wavelengths of the electromagnetic spectrum while transmitting shorter wavelengths
• B. it absorbs shorter wavelengths of the electromagnetic spectrum while transmitting longer wavelengths
• C. it absorbs all wavelengths of the electromagnetic spectrum
• D. it transmits all wavelengths of the electromagnetic spectrum

Answer 1

Answer: (A)

Heat through sun reaches earth in form of infrared radiations of higher frequency range approx $10^{14}Hz$. This heat is absorbed by solids on earth's surface and they re-radiate this heat in form of infrared radiations of lower frequency range approx $10^{10}Hz$. These radiations are absorbed by greenhouse gases like methane and does not escapes into space causing warming of earth's atmosphere.