The colour of light which is scattered the most by the atmospheric molecules is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Blue
Scattering of sunlight by molecules much smaller than the wavelength is Rayleigh scattering, whose intensity is inversely proportional to the fourth power of the wavelength.
\( \displaystyle I_{\mathrm{s}} \propto \frac{1}{\lambda^{4}} \)
So the shortest wavelength is scattered the most. Among red, yellow, green and blue, blue has the shortest wavelength, so it is scattered the most; this is why the clear sky looks blue.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Scattering of Light – “… Light of shorter wavelengths is scattered much more than light of longer wavelengths. (The amount of scattering is inversely proportional to the fourth power of the wavelength. This is known as Rayleigh scattering). Hence, the bluish colour predominates in a clear sky, since blue has a shorter wavelength than red and is scattered much more strongly.”