Question

A plano-convex lens fits exactly into a plano- concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices, $μ_1$ and $μ_2$ and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is

• A. $\frac{R}{2(μ_1 +μ_2)}$
• B. $\frac{R}{2(μ_1 - μ_2)}$
• C. $\frac{R}{(μ_1 - μ_2)}$
• D. $\frac{2R}{(μ_2 - μ_1)}$

Answer 1

The Correct Option is C

The correct option is (C): $\frac{R}{(μ_1 - μ_2)}$