Question

Angle of prism is ‘A’ and its one surface is silvered. Light rays falling at an angle of 2A and travels through the same path after suffering reflection at second silvered surface. The refractive index of the material of the prism is

• A. 2 sin A
• B. 2 cos A
• C. $\frac{1}{2}$ cos A
• D. tan A

Answer 1

The correct option is B 2 cos A

$i_1=2AandA=r_{1}and\mu =\frac{sini}{sinr}=\frac{sin2A}{sinA}=2cosA$