WBCS.LIVE practice question

‘Red’ is used as a danger signal because

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. blood is red.
  2. red light is scattered least by the air molecules.
  3. red colour is easily available.
  4. red colour is soothing for eye.

Correct answer and explanation

Correct answer: red light is scattered least by the air molecules.

Explanation: ✅ Correct Answer: B) red light is scattered least by the air molecules. 📚 Explanation: Red light has the longest wavelength in the visible spectrum, which means it is scattered the least by dust and air molecules (Rayleigh scattering). Because it travels through the atmosphere with less interference, it can be seen from a much greater distance even in fog or rain. This makes it ideal for danger signals.