Question

A ray OA is incident upon a smooth surface POQ. It is reflected back along OB. A normal ON is drawn perpendicular to the surface at O (the point of incidence). The value of $\angle AOP$ is ${60}^{\circ }$ . Find the value of the angle of reflection.

• A. 55
• B. 63
• C. 100
• D. 26

Answer 1

The correct option is A

55

$\angle AOP+\angle AON={90}^{\circ }$ (as ON is perpendicular to POQ)

$\Rightarrow \angle AON={90}^{\circ }-{60}^{\circ }$ (as $\angle AOP={60}^{\circ }$ )
$\Rightarrow \angle AON={30}^{\circ }$

Now, $\angle AON=\text{angle of incidence = angle of reflection}=\angle BON$

Thus, the angle of reflection $={30}^{\circ }$