Question

Match the following :

LIST I	LIST II
A) Rainbow	1) Scattering of light
B) Twinkling of stars	2) Dispersion of light
C) Blue colour of sky	3) Fluctuation of the refraction index in atmosphere layers
D) Advancement of sunrise and delay of sunset	4) Refraction of light

• A. A-1,B-2,C-4,D-3
• B. A-2,B-3,C-1,D-4
• C. A-3,B-4,C-2,D-1
• D. A-4,B-1,C-3,D-2

Answer 1

Answer: (B)

A-2,B-3,C-1,D-4

A. Rainbow is due to dispersion of light (2) in water droplets resulting in a spectrum of light appearing in the sky.
B. Twinkling of stars is because of multiple refraction (fluctuation of refraction index) of light through thick layers of turbulent (moving) air in the Earth's atmosphere. (3)
C. Blue of sky is due to scattering of light by the tiny molecules of air in Earth's atmosphere. (1)
D. Advancement of sunrise and delay of sunset is due to refraction of light (4).
During sunrise, when the sun is just below the horizon, our atmosphere causes the light rays to bend and we see the sun early. Similarly, at sunset, the apparent position of the sun is visible to us and not the actual position due to the same bending of light rays effect.