If the angle of incidence is at 30∘, find the angle of deflection, after reflecting 2 times.
Deviation at first point of incidence = π - (2i)
= π - 2 (30∘)
= π - 60∘ = 120∘
Deviation at second point of incidence = π - 2i
= π - 2 (30∘)
= 120∘
Total deviation = 240∘