Match List-I with List-II
| List-I | List-II |
| (A) The refraction in lenses occurs | (I) Incidence angle in the denser medium is greater than the critical angle for the two media |
| (B) Total internal reflection can occur | (II) when a ray from a denser medium is incident onto a rarer medium. |
| (C) In total internal reflection, the whole energy of the incident ray | (III) remains reflected in the denser medium. |
| (D) Total internal reflection occurs only when | (IV) at all possible angles of incidence |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) - (IV), (B) - (II), (C) - (III), (D) - (I)
When light goes from a denser to a rarer medium, it bends away from the normal. At the critical angle C the angle of refraction becomes 90°; for any larger angle of incidence no refracted ray forms and all the light is reflected back. This is total internal reflection (TIR). Going from rarer to denser, a refracted ray always exists.
(A) The refraction in lenses occurs — this matches (IV) at all possible angles of incidence. Light enters a lens from air into glass (rarer to denser), so it is refracted at every angle.
(B) Total internal reflection can occur — this matches (II) when a ray from a denser medium is incident onto a rarer medium. Only then does a critical angle exist, so this condition makes TIR possible.
(C) In total internal reflection, the whole energy of the incident ray — this matches (III) remains reflected in the denser medium. No light passes into the rarer medium; that is why it is called total.
(D) Total internal reflection occurs only when — this matches (I) Incidence angle in the denser medium is greater than the critical angle for the two media. Denser to rarer is not enough by itself; the angle must also exceed C for TIR to happen.
NCERT (2026-27):
Total Internal Reflection – “When light travels from an optically denser medium to a rarer medium at the interface, it is partly reflected back into the same medium and partly refracted to the second medium. This reflection is called the internal reflection.”
Total Internal Reflection – “… If the angle of incidence is increased still further (e.g., the ray AO4), refraction is not possible, and the incident ray is totally reflected. This is called total internal reflection. … In total internal reflection, on the other hand, no transmission of light takes place. The angle of incidence corresponding to an angle of refraction 90°, say ∠AO3N, is called the critical angle (ic) for the given pair of media.”