Question

A ray parallel to principle axis hits a concave mirror of radius of curvature R and passes through pole after reflection. Height 'h' of ray from principle axis is

• A. R
• B. $\frac{R}{\sqrt{2}}$
• C. $\frac{\sqrt{3}}{2}R$
• D. $\frac{R}{2}$

Answer 1

The correct option is C $\frac{\sqrt{3}}{2}R$


$\theta ={60}^{\circ }\Rightarrow sin60=\frac{h}{R}\Rightarrow h=\frac{\sqrt{3}}{2}R$