0
$\begingroup$

If there are two identical lenses L1 and L2 but made with different materials such that refractive index of one is greater than the other (Say for L1 = 1.33 and L2 = 2.13). Will it affect in any way? Is there a change in focal length or where the image is formed? Please explain.

$\endgroup$
1
  • 5
    $\begingroup$ Yes, the focal length is dependent on the optical density of the material. See- Lens Maker's Formula $\endgroup$
    – Sam
    Jan 18, 2020 at 13:01

1 Answer 1

1
$\begingroup$

A lens works because it has a different refractive index from the medium it is in. The bigger that difference, the stronger the lens is for a given shape.

That also means the focal length of a glass lens in air is less than its focal length in water. The smaller difference in refractive index makes it weaker.

$\endgroup$
2
  • $\begingroup$ So, the focal length doesn't have to be half of the Radius of curvature (I have seen the relation R= 2f )? $\endgroup$ Jan 18, 2020 at 16:09
  • 2
    $\begingroup$ The relationship $R=2f$ is for a concave mirror, not for a lens. $\endgroup$ Jan 18, 2020 at 16:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.