Does focal length of lens change with change in refractive index?

Question

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.

DrC · Answer

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.

Does focal length of lens change with change in refractive index?

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