Question

A ray of light is incident normally on one of the faces of a prism of apex angle ${30}^{\circ }$ and refractive index $\sqrt{2}$. The angle of deviation of the ray is _________ degrees.

Answer 1

Using Snell's law for the refraction at $AC$,
we get $\mu \sin i=\left(1\right)\sin r\sqrt{2}\sin {30}^{\circ }=\sin r$.
$\sin r=\frac{1}{\sqrt{3}}r={45}^{\circ }$
Angle of deviation $={45}^{\circ }-{30}^{\circ }={15}^{\circ }$