The angle between an incident ray and the mirror is 30º:
a) What is the angle of incidence?
b) What is the angle of reflection?
c) What is the total angle turned by the ray?
Angle of incidence is the angle between the normal to the mirror and the incident ray, so here that is 90 - 30 or 60 degrees.
The angle of reflection is the same, namely, 60 degrees.
Total angle turned through by the ray is 360 - 60 - 60 = 240 degrees.
