Try it yourself
Question
What is the angle of reflection from the second mirror?
- The angle of incidence at mirror A = 70o
- i = r and so the angle of reflection at mirror A = 70o
- The angle between the reflected ray and the mirror = 20o. The angle of incidence at mirror B is an alternate angle and so also equals 20o
- i = r and so the angle of reflection at mirror B = 20o