1. Tardigrade
  2. Question
  3. Physics
  4. A plano-convex lens (focal length f2, refractive index μ2, radius of curvature R) fits exactly into a plano-concave lens (focal length f1, refractive index μ2, radius of curvature R). Their plane surfaces are parallel to each other. Then, the focal length of the combination will be :

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

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

JEE MainJEE Main 2019Ray Optics and Optical Instruments

Solution:

$\frac{1}{F} \, = \, \frac{1}{f_1} + \frac{1}{f_2} = \frac{1-\mu_1}{R} + \frac{\mu_2 - 1}{R}$

Solution Image