Why do clouds appear white?

Explanation

(i) If light is scattered by large particles like dust and water droplets present in the atmosphere which have size a greater than the wavelength `lamda` of light, `a gt gt lamda`, the intensity of scattering is equal for all the wavelengths.
(ii) It is happening in clouds which contains large amount of dust and water droplets.Thus, in clouds all the colours get equally scattered irrespective of wavelength. This is the reason for the whitish appearance of cloud.