Question

A light ray is incident, at an incident angle $\theta_{1}$, on the system of two plane mirrors $M _{1}$ and $M _{2}$ having an inclination angle $75^{\circ}$ between them (as shown in figure). After reflecting from mirror $M_{1}$ it gets reflected back by the mirror $M _{2}$ with an angle of reflection $30^{\circ}$. The total deviation of the ray will be .............. degree.

Answer 1

$\delta_{\text {total }}=360^{\circ}-2 \theta$
$=360^{\circ}-2 \times 75^{\circ}$
$\delta_{\text {totakl }}=210^{\circ}$

$\theta_{1} = 45^{\circ}$

$\delta=120^{\circ}+90^{\circ}=210^{\circ}$