JAMB - Physics (2000 - No. 41)

An engineer intends to deviate a light ray from its path by 120^o through reflection from a plane mirror. Calculate the angle of incidence

60^o

40^o

30^o

20^o

Angle of deviation = 180 - [i + v]
= 180 - 2i [since i = v]
∴ 120 = 180 - 2i
2i = 180 - 120
= 60
∴ i = 30^o