Question

why is the sky blue in colour

Answer 1

heya !!

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The blue colour of sky is due to the scattering of light by small particles of the atmosphere (air molecules) when the light is incident on particles whose size is smaller than the wavelength of light, it is scattered.As the wavelength of blue colour is smallest and that of red light is longest, the blue light is scattered most and the red light is scattered least. The scattered blue light reaching the eye gives the appearance of a blue sky. The sky will appear black in the absence of earth’s atmosphere because no scattering of any colour takes place in that case. While flying in an aeroplane one can observe the sky to be black at high altitudes.

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Answer 2

The light from sun has to travel a long distance of the earth's atmosphere before reaching us. As light travels through the atmosphere, it gets scattered in different directions by the air molecules present in the path. The blue light due to its short wavelength is scattered more as compared to the red light of long wavelength. Thus the light reaching our eye directly from sun is rich in red colour, while the light reaching our eye from all other directions is the scattered blue light. Therefore the sky in direction, other than the direction of sun, is seen blue.