Consider two limiting arrangements of a pair of plane mirrors: Case
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
Consider two limiting arrangements of a pair of plane mirrors:
Case (A) the mirrors are perpendicular (ϕ=90∘) and
Case (B) the mirrors are parallel (ϕ=0∘). A light ray lies in the plane of the mirrors and undergoes exactly two successive reflections, first from one mirror and then from the other.
(i) For Case (A), prove that the emergent ray is always parallel to the incident ray, whatever be the initial direction of the ray.
(ii) For Case (B), explain why the emergent ray retraces the incident path. Support your explanation with a suitable ray diagram.
(iii) Compare and contrast the deviation produced in the two limiting cases with that produced when 0∘<ϕ<90∘. Comment briefly on the physical significance of your result.