Question:
The clanger signals installed at the top of tall building are red in colour. These can be seen from a distance because among all other colours, the red light
(a) is scattered the most by smoke or fog
(b) is scattered the least by smoke or fog
(c) is absorbed the most by smoke or fog
(d) moves fastest in air
Solution:
(b).
Explanation : Intensity of scattered light, I ∝ 1/λ4 . Since the wavelengths of red light is greater than the wavelengths of all other lights, therefore,
red colour can be seen from a distance.
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