Question

A ray of light is incident at an angle of ${35}^0$ on a plane mirror. What is angle $\theta$?

Answer 1

Angle of incidence $i=90-35={55}^o$

From laws of reflection, angle of reflection $r=i={55}^o$

Thus $\theta ={180}^o-i-r-{35}^o$

$⟹\theta ={180}^o-{55}^o-{55}^o-{35}^o={35}^o$