Q108
General SciencePhysics
'Red' is used as a danger signal because
- a.blood is red
- b.red light is scattered least by the air molecules
- c.red colour is easily available
- d.red colour is soothing for eye
Answer: (B) red light is scattered least by the air molecules
Red light, having the longest wavelength among visible colours, is scattered the least by air molecules (Rayleigh scattering), allowing it to travel and remain visible over the greatest distance — the same principle behind traffic signal design.