Question

Study carefully the following figure representing greenhouse effect.

Select the correct statements regarding this.

• A. Much of the long wavelength infrared radiations re-radiated by the earth's surface are absorbed by the atmospheric greenhouse-gases
• B. $CO_{2}$ , $CH_{4}$ , $CFCs$ and $N_{2}O$ are the gases which responsible for greenhouse effect
• C. The atmosphere is transparent to the incoming short-wavelength radiations and is translucent to the tong-wavelength infra-red radiations
• D. All of these

Answer 1

Answer: (D)

Various greenhouse gases like CO​​​​​₂, H₂O, NO₂, methane (CH₄) and, CFCs are essential for keeping the Earth warm and hospitable by preventing a substantial part of long wave radiation which are emitted by Earth to escape into space. Greenhouse gases cause the Greenhouse effect, which is a naturally occurring phenomenon, responsible for the heating of the earth's surface as well as atmosphere. Greenhouse gases allow short wavelength radiations (like UV radiations) to come in but do not allow long-wave radiations to go out, so they absorb long-wave (infrared) radiations from the earth and emit it again towards the earth. This downward flux of radiation is called "greenhouse flux". This cycle continues till there are no long-wave radiations left to emit from the earth's surface. If there were no greenhouse effect, the Earth’s average surface temperature would be a very chilly $$ -18°C ( $$ 0°F) instead of the comfortable $$ 15°C ( $$ 59°F) that it is today.