Match the LIST-I with LIST-II
| LIST-I (Observation) | LIST-II (Phenomenon) |
| A. Blue colour of the sky | I. Total internal reflection of light |
| B. Shining of diamond | II. Refraction of light |
| C. Colours in soap bubble | III. Scattering of light |
| D. Twinkling of stars | IV. Interference of light |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-III, B-I, C-IV, D-II
Each everyday observation is explained by one optical phenomenon.
(A) Blue colour of the sky — this matches (III) Scattering of light. Air molecules scatter short wavelengths much more strongly (Rayleigh scattering, intensity \( \propto 1/\lambda^{4} \)), so scattered blue light reaches the eye from all directions.
(B) Shining of diamond — this matches (I) Total internal reflection of light. Diamond has a very high refractive index (about 2.42) and so a small critical angle (about 24°); light entering it is totally reflected many times before it comes out.
(C) Colours in soap bubble — this matches (IV) Interference of light. Light reflected from the two surfaces of the thin film interferes, and different thicknesses reinforce different colours.
(D) Twinkling of stars — this matches (II) Refraction of light. Starlight is refracted by layers of air whose density keeps changing, so the apparent position and brightness of the star keep changing.