Question

A ray of light strikes a plane mirror $M$ at an angle of $45^{\circ }$ as shown in the figure. After reflection, the ray passes through a prism of refractive index $1.5$ whose apex angle is $4^{\circ }$. The total angle through which the ray is deviated is

• A. $90^{\circ }$
• B. $91^{\circ }$
• C. $92^{\circ }$
• D. $93^{\circ }$

Answer 1

Answer: (C)

As, ${\delta }_{\text{net }}={\delta }_{\text{mirror }}+{\delta }_{\text{prism }}$
$=(180-2i)+(\mu -1)A=(180-2\times 45)+(1.5-1)\times 4=92^{\circ }$