Question:-
Why skies are blue but not other colours ?
Answer:-
Skies are blue due to the scattering of sunlight by the molecules of the atmosphere. When sunlight passes through the atmosphere, then nitrogen and oxygen molecules present in the atmosphere absorb a part of sunlight and re-emit it. Free gas molecules of the atmosphere scatter light in all direction but according to Rayleigh's law of scattering as the intensity of scattered light is inversely proportional to the fourth power of wavelength of light, the light of short wavelength (blue) is scattered more than the light at the long wavelength (red end). For this reason, when we look at the sky, the scattered light enters into our eyes which contains blue colour in a larger proportion and hence skies are blue.
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