CAPF AC 2022 PYQ with Answer — The optical phenomenon responsible for the blue colour of sky is

2022 · Q48

The optical phenomenon responsible for the blue colour of sky is

general-sciencephysics-light-electricity

Adispersion
Breflection
Crefraction
Dscattering

Explanation

The blue colour of the sky is caused by scattering — specifically Rayleigh scattering of sunlight by air molecules, which scatters shorter (blue) wavelengths far more strongly (∝ 1/λ⁴) than longer (red) wavelengths. Dispersion (option A) separates white light into a spectrum (as in rainbows); reflection (option B) and refraction (option C) do not selectively scatter blue light across the sky. Hence option D.