Question

converging or diverging power of a lens depends upon the difference of reflective index of lens with respect to the medium in it is placed if a converging lens having power P is immersed in a liquid its focal length will be

Answer 1

Answer:

The ability of a lens to act as converging or diverging depends upon its refractive index. The refractive index n of the material of a lens depends upon the medium in which the lens is placed. Generally the lens is in air so n gives refractive index of material of lens with respect to air.

Focal length depends upon refractive index of lens with respect to medium.

Since the absolute refractive index of water is more less than that of glass. Hence, after immersing of lens in water focal length of lens increases. A convex lens made of glass is immersed in water. As a result,its focal length will increase.