Question

The refractive index of glass with respect to air is 2. The critical angle at their interface i

• A. 30°
• B. 45°
• C. 60°
• D. 90°

Answer 1

The Correct Option is A

The critical angle \( \theta_c \) is given by the formula: \[ \sin \theta_c = \frac{n_2}{n_1} \] Here, \( n_1 = 2 \) (glass), \( n_2 = 1 \) (air), so \[ \sin \theta_c = \frac{1}{2} \Rightarrow \theta_c = \sin^{-1} \left( \frac{1}{2} \right) \Rightarrow \theta_c = 30^\circ \]

The correct answer is option (A): \(30°\)