Q. If in a plano-convex lens, the radius of curvature of the convex surface is $10\ cm$ and the focal length of the lens is 30 $cm$, then the refractive index of the material of lens will be
A) 1.5
B) 1.66
C) 1.33
D) 3
Explanation
(c) $f = \frac{R}{(\mu - 1)} \Rightarrow 30 = \frac{10}{(\mu - 1)} = \mu = 1.33$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.