A plano-convex lens is to have a focal length of magnitude 40 cm, and it is made of glass of index of refraction 1.65. What radius of curvature is required?
A) 26 cm
B) 36 cm
C) 13 cm
D) 32 cm

Question

Quizplus · Accepted Answer

Using the lensmaker's equation for a plano-convex lens, $ \frac{1}{f} = (n - 1) \left( \frac{1}{R} \right) $, where $ f = 40 $ cm and $ n = 1.65 $, solving for $ R $ gives $ R = 26 $ cm.

A Plano-Convex Lens Is to Have a Focal Length of Magnitude