Question

Two plane mirrors are perpendicular to each other . A ray of light , after reflecting from the first mirror , reflects from the second mirror. The angle between the original ray and the reflected ray from the second mirror is ​

Answer 1

Answer:

Let ray strikes the vertical mirror by angle of incidence θ. Then by joining the perpendiculars of two mirrors it is clear from the diagram that angle of incidence at horizontal mirror is (90−θ).

∴ reflected ray from horizontal mirror makes angle θ with the horizontal mirror also incident ray at vertical mirror makes angle θ with horizontal axis.

∴ reflected ray is parallel to the original ray.

This is true for two perpendicular mirrors fixed at any positions.