Question

A ray of light is incident on a plane mirror at an angle of $60^{\circ }$. The angle of deviation produced by the mirror is

• A. 30${}^{\circ }$
• B. 60${}^{\circ }$
• C. 90${}^{\circ }$
• D. 120${}^{\circ }$

Answer 1

Answer: (B)

Here, angle of incidence, $i=60^{\circ }$

$\therefore$ Angle of deviation
$\delta =180^{\circ }-(i+r)$
$=180^{\circ }-2i(\text{ As }i=r)$
$=180^{\circ }-2\times 60^{\circ }=60^{\circ }$