Chapter 18, Problem 90A

To determine

To explain: The reason for the non functioning of the the magnifying lens in water .

Explanation of Solution

Introduction:

Magnifying lens is used to get the enlarged image of an object under observation. Normally, a convex lens is used as a magnifying lens. The magnifying power of the lens is mainly governed by the difference between the refractive index of the lens and that of its surrounding medium. When light passes from one medium to another, bending will occur only when there is a difference in the refractive index of the two media.

The difference between the refractive index of water and the lens is comparatively smaller than that of between air and lens. Hence magnifying power of lens is considerably less in water than that in air. Therefore the magnifying lens is not working very well in water as it would in air.