A plano-convex lens...|GEOMETRICAL OPTICS|JEE_MAIN

JEE MAIN 2019

12-01-2019 S2

Question

A plano-convex lens (focal length $f_2$, refractive index $\mu_2$, radius of curvature $R$ ) fits exactly into a planoconcave lens(focal length $f_1$, refractive index $\mu_1$, radius of curvature $R$ ). Their plane surfaces are parallel to each other. Then, the focal length of the combination will be:

Select the correct option:

$f_1-f_2$

$\frac{\mathrm{R}}{\mu_2-\mu_1}$\

$\frac{2 f_1 f_2}{f_1+f_2}$

$f_1+f_2$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution