Greenhouse gases absorb radiation energy mostly in which of the following…

Concept

Greenhouse gases interact selectively with radiation according to wavelength.

Most incoming shortwave sunlight passes through the atmosphere, while molecules such as carbon dioxide, water vapour, and methane absorb and re-emit longwave thermal radiation through their rotational and vibrational modes.

Application

X-rays, ultraviolet, infrared, and visible radiation occupy different wavelength bands. Molecular rotational and vibrational transitions fall mainly in the infrared band, which also contains much of the thermal radiation emitted by Earth’s warmed surface. Hence the relevant region is Infra-red.

Contrast

• X-Ray radiation consists of very short-wavelength, ionizing photons and is absorbed mainly in the upper atmosphere.

• Ultraviolet radiation drives electronic transitions, and ozone is its major atmospheric absorber.

• Visible radiation forms the atmospheric window through which much incoming sunlight reaches the surface.

Cross-check

By the Wien displacement law, a surface near 288 K emits most strongly at about 10 micrometres, which lies in the thermal infrared. This matches the absorption bands responsible for the greenhouse effect.

Therefore, the radiation region is Infra-red.