Question

give reason why the colour of clear sky is blue

Answer 1

A clear cloudless day-time sky is bluebecause molecules in the air scatter bluelight from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange coloursbecause the blue light has been scattered out and away from the line of sight.

Answer 2

Hey there ;

The molecules of air and other fine particles in the atmosphere have size smaller than the wavelength of visible light. These are more effective in scattering light of shorter wavelengths at the blue end than light of longer wavelengths at the red end. The red light has a wavelength about 1.8 times greater than blue light. Thus, when sunlight passes through the atmosphere, the fine particles in air scatter the blue colour more strongly then red.

Hope it helps you !