Question

A plane mirror deviates a light ray by 80 degree what is the angle of incidence​

Answer 1

Answer:

$\huge \underline \mathfrak \red{Answer}$

Suppose a ray of light is incident on 1st mirror at angle i. Hence, deviation at 1st mirror is 2i. Now this ray will incide on 2nd mirror at angle 80-i. So deviation at 2nd mirror is 2(80-i) = 160-2i.