Question

A ray is incident from a medium of refractive index 2 to another with refractive index 1. The critical angle is:

• A. \( 30^\circ \)
• B. \( 60^\circ \)
• C. \( 45^\circ \)
• D. \( 90^\circ \)

Hint:

Critical angle applies when light goes from denser to rarer medium: \( \sin \theta_c = \frac{n_2}{n_1} \).

Answer 1

The Correct Option is A

Critical angle \( \theta_c \) is given by: \[ \sin \theta_c = \frac{n_2}{n_1} = \frac{1}{2} \Rightarrow \theta_c = \sin^{-1} \left( \frac{1}{2} \right) = 30^\circ \]