Physics · Total internal reflection and its applications, magnification, power of a lens, combination of thin lenses in contact

The danger signals installed at the top of tall buildings are red in colour. The

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

Step-by-step solution

Red light has the longest wavelength among visible colors, so it undergoes the least Rayleigh scattering by particles like smoke or fog, making it more visible from a distance.
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