Question

A ray parallel to the principal axis is incident at 30° from normal on a concave mirror having a radius of curvature R. The point in principal axis where rays are focussed is Q such that PQ is 

• A. \( \dfrac{R}{2} \)
• B. \( \dfrac{R}{\sqrt{3}} \)
• C. \( \dfrac{2\sqrt{R}}{\sqrt{2}} \)
• D. R(1 - \dfrac1√(3))

Hint:

For mirror problems involving angles: 
• Normal always passes through center of curvature. 
• Use simple trigonometry with reflected rays.

Answer 1

The Correct Option is B