Do Greenhouse gases absorb only Infrared or a a range of wavelengths ? Please specify the Range of wavelengths of radiations which are absorbed by Greenhouse Gases
Infrared radiations are of order 10^-5 so they should be considered shorter. Am I Right ?
Anyhow, The exact question is as follows-
Q. Methane is a Greenhouse Gas because-
A) it absorbs longer wavelenghts of the electromagnetic spectrum while transmitting shorter wavelenghts
B) it absorbs shorter wavelenghts of the electromagnetic spectrum while transmitting longer wavelenghts
C) it absorbs all wavelenghts of the electromagnetic radiation
D) it transmits all wavelenghts of the electromagnetic radiation
Thank You in Advance
The correct answer is A, Methane is a greenhouse gas because it absorbs longer wavelengths of light while transmitting shorter wavelengths.
Specifically, the longer wavelengths it absorbs are infrared.
Greenhouse gases typically absorb in the infrared part of the spectrum, which has wavelengths ranging from about 10^(-6) to 10^(-3) meters. The energy from the absorbed infrared photons causes greenhouse gas molecules to vibrate until they re-emit the infrared light. This ability to absorb and re-emit infrared is what causes greenhouse gases to trap heat in the lower atmosphere.
Infrared radiation is longer in wavelength relative to the other wavelengths reaching the earth from the sun. Visible light is shorter, having wavelengths of the magnitude 10^(-7). Ultraviolet is shorter than visible, and is mostly absorbed by ozone and water vapor in the upper atmosphere.