When a ray of light enters from one medium to another, its velocity is doubled. The critical angle in the denser medium will be
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 30°
The velocity doubles, so light is going from the denser to the rarer medium. The refractive index of the denser medium relative to the rarer is the ratio of the speeds, and the critical angle satisfies \( \sin C = 1/n \).
\( \displaystyle n = \frac{v_{\mathrm{rarer}}}{v_{\mathrm{denser}}} = \frac{2v}{v} = 2 \)
\( \displaystyle \sin C = \frac{1}{n} = \frac{1}{2} \)
\( \displaystyle C = 30^\circ \)
Note: The same question was also asked in CUET (UG) 2023 on 15-06-2023 (Slot 2).