Question

Fig. shows an incident ray $AO$ and the normal $ON$ on a plane mirror. The angle which the incident ray $AO$ makes with the mirror is ${30}^{\circ }$. Draw the reflected ray and then find the angle between the incident and reflected rays.

Answer 1

Following the law of reflection, the angle of incidence is equal to the angle of reflection, we can draw the reflected ray.
Hence,
$\angle i=\angle r={90}^{\circ }-{30}^{\circ }={60}^{\circ }$
(using basic geometry, and law of reflection)
Therefore, the angle between the incident ray and the reflected ray,
$=\angle i+\angle r={60}^{\circ }+{60}^{\circ }={120}^{\circ }$