Match the LIST-I with LIST-II
| LIST-I | LIST-II | ||
| (Observation) | (Phenomenon) | ||
| A. | Brilliance of Diamond | I. | Scattering of light |
| B. | Reddish sun at sunset | II. | Refraction |
| C. | Dark and bright bands | III. | Total internal reflection |
| D. | Twinkling of Stars | IV. | Interference of light |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A - III, B - I, C - IV, D - II
Each observation is explained by one optical phenomenon.
(A) Brilliance of Diamond — this matches (III) Total internal reflection. Diamond’s high refractive index (about 2.42) gives a small critical angle, so light is totally reflected many times inside.
(B) Reddish sun at sunset — this matches (I) Scattering of light. Over the long air path at sunset, blue light, scattered most (\( \propto 1/\lambda^{4} \)), is removed, leaving mostly red.
(C) Dark and bright bands — this matches (IV) Interference of light. Fringes form where coherent waves meet in phase and out of phase.
(D) Twinkling of Stars — this matches (II) Refraction. Air layers of changing density refract starlight, so the star appears to flicker.
Note: Only (C), interference bands, is in the latest textbook (2026-27). (A), the brilliance of diamond, and (B), the reddish sun at sunset, are printed only in the pre-rationalised textbook (2022-23). Total internal reflection is still in the CUET 2026 syllabus, so do not skip (A); scattering of light appears to be out of the CUET 2026 syllabus. (D), the twinkling of stars, is not in either Class 12 textbook.
NCERT (2026-27):
Interference of Light Waves and Young’s Experiment – “… Thus dark and bright bands appear on the screen, as shown in Fig. 10.13. Such bands are called fringes.”
NCERT (Pre-rationalised edition, 2022-23):
Total Internal Reflection in Nature and Its Technological Applications – “… (ii) Diamond: Diamonds are known for their spectacular brilliance. Their brilliance is mainly due to the total internal reflection of light inside them.”
Scattering of Light – “… At sunset or sunrise, the sun’s rays have to pass through a larger distance in the atmosphere (Fig. 9.28). Most of the blue and other shorter wavelengths are removed by scattering. The least scattered light reaching our eyes, therefore, the sun looks reddish.”