A simple periscope consists of two identical plane mirrors placed at its ends
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
A simple periscope consists of two identical plane mirrors placed at its ends, each inclined at 45∘ to the horizontal line of sight of an observer.
(a) With the help of a ray diagram, explain how such an arrangement allows the observer to see over a high wall.
(b) A horizontal light ray enters the periscope, is reflected by the top mirror and then by the bottom mirror, and finally emerges horizontally. If the top mirror is rotated by 2∘ about a vertical axis while the bottom mirror remains fixed, calculate the angular deviation of the emergent ray from its original direction.
(c) State any two practical advantages of using mirrors inclined at 45∘ in a periscope.