Chapter 18, Problem 58A

To determine

The factor that specifies the location of the focal point of the lens.

Explanation of Solution

Introduction:

The point at which the light rays, that are parallel to the optical axis of a lens, diverges after passing through that lens is called focal point of a concave lens. The light rays that are parallel to the optical axis of a convex lens gets converging to a point after passing through that lens. This point is called focal point of the convex lens.

Apart from the curvature of the surfaces of a lens, the focal point of the lens also depends on the refractive index of the material that is used to prepare the lens. If the refractive index of the material used to form the lens is increased, then the focal point is closer to the lens otherwise it will be far away from the lens.