Question

A magnifying glass is made of a combination of a convex lens of power +20 D and a concave lens of power -4 D. If the least distance of distinct vision of the eye is 0.25 m, calculate the magnifying power.

a. +16 D
b. -16 D
c. +5 D
d. -5 D

Answer 1

The magnifying power of a combination of a convex lens of power +20 D and a concave lens of power -4 D is +16 D

Step-by-step explanation:

To calculate the magnifying power of a combination of lenses, we need to add the powers of the individual lenses. The power of a lens is the reciprocal of its focal length measured in meters. The combined power of a convex lens with power +20 D and a concave lens with power -4 D is 16 D. Therefore, the correct option is a. +16 D.