Question

Light traveling in glass n=3/2 is incident on-air n=1. What is the angle of incidence that causes the light to experience total internal reflection?

Answer 1

The critical angle is given by

$$\theta_c=\sin^{-1}\frac{n_2}{n_1}$$

$$\theta_c=\sin^{-1}\frac{1}{3/2}=41.8^\circ$$

$$\theta \geq\theta_c$$