The danger signals installed at the top of tall buildings are red in colour. These can be easily 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
- Red light has the longest wavelength and is hence least scattered are air/smoke/fog.
- This makes it easier to see danger signs even at a distance.
So, the correct answer is (b)