(Extended Reasoning on Mirror Rotation) A narrow beam of light falls on a plane…
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
(Extended Reasoning on Mirror Rotation)
A narrow beam of light falls on a plane mirror at point O. Initially, the incident ray, the normal and the reflected ray all lie in a vertical plane that is perpendicular to the mirror surface. The mirror is now rotated through an angle of 15° about the normal at O, while the incident ray is kept fixed in its original direction.
(a) Using geometrical reasoning, prove that the incident ray, the normal and the new reflected ray continue to lie in a single plane.
(b) Show that the angle between the initial and the new reflected rays is twice the angle through which the mirror is rotated.
(c) Calculate the angle through which the reflected ray turns for the given rotation of the mirror.