Question

the incident ray and the reflected ray from a mirror are mutually perpendicular to each other find angle of incidence

Answer 1

Angle of incidence=Angle of reflection(2nd law of reflection).
So, angle of incidence=90 degree.

Answer 2

Answer:

The angle of incidence= angle of reflection.

so i=r

i+r=90

i+i=90

i =45