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NDA 1 2025 GAT, question 136

Topic: Physics

Q136

What happens when the sunlight travels through the Earth’s atmosphere ?

  1. (a) The blue colour is scattered more compared to the red colourCorrect answer
  2. (b) The red colour is scattered more compared to the blue colour
  3. (c) Both the blue and the red colours are scattered equally
  4. (d) The blue colour is not scattered but the red colour is scattered the most

Solution.

Answer: (a) The blue colour is scattered more compared to the red colour

  1. Air molecules scatter shorter wavelengths more strongly than longer wavelengths.
  2. In the Rayleigh-scattering approximation, intensity is proportional to 1/λ41/\lambda^{4}.
  3. Blue light has a shorter wavelength than red light, so blue is scattered more strongly.