Question

why does sky appear blue in day

Answer 1

When the rays of the sun,falls on the atmosphere it absorbs other colour but blue color is reflected by it which reaches our eyes that's why it appears blue in day light.

Answer 2

the particles present in atmosphere are very tiny. they scatter only light of shorter wavelength. as the blue colour has the shorter wavelength and red colour has has the longer wavelength as 8 times the blue colour. during the scattering of light, the light of longer wavelength are scattered out and only blue colour reaches our eyes