Question

An incident ray makes an angle of ${30}^o$ with the surface of plane mirror. What is the angle between incident ray and reflected ray?

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

Answer 1

The correct option is D ${120}^o$

Incident ray makes ${30}^o$ with the plane mirror,
But taking Normal
$\text{Angle of incidence}={90}^o-{30}^o={60}^o$
$\text{According to laws of reflection,}$
$\text{angle of incidence}=\text{angle of reflection}$
$\text{so, angle of reflection}={60}^o$
Angle between incident ray and reflected ray is ${60}^o+{60}^o={120}^o$