Physics
Give reasons for the following:
During the day:
(i) Clouds appear white.
(ii) Sky appears blue.
Spectrum
ICSE 2020
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Answer
(i) Clouds are dust particles and water molecules suspended in the atmosphere near the earth of size bigger than the wavelength of visible light. Thus, they scatter all colours of incident white light from the sun to the same extent and hence when scattered light reaches our eyes, the clouds appear white.
(ii) The air molecules in the atmosphere scatter the blue end of spectrum having shorter wavelengths much more than colours on the red end. In the absence of direct light from sun, the light reaching our eyes is the scattered light which is rich in blue colour. Hence, light from all directions of sky being rich in blue colour makes the sky appear blue.
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