Question

A ray of light is incident on a plane mirror at an angle of incidence of ${30}^o$. The deviation produced by the mirror is:

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

Answer 1

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

Since angle of incident =angle of reflection

Hence $r={30}^0$

And here angle of deviation,

$\delta ={180}^0-(i+r)$

$\delta ={120}^0$