Question

Trace the path of a ray of light passing through a glass prism $ABC$ as shown in the figure. If the refractive index of glass is $\sqrt{3}$, then find out the value of the angle of emergence from the prism.

Answer 1

The incident ray is normal to side AC. So angle of incidence and reflection is 0 fro Snell’s law.

At AC,

$\frac{\sin i}{\sin r}=\frac{n_g}{n_a}$

At AB $\angle i={30}^0$

Applying Snell’s law again at this interface

$\frac{\sin 30}{\sin e}=\frac{n_a}{n_g}$

$\frac{1}{2\sin e}=\frac{1}{\sqrt{3}}$

$e={60}^0$