Wave Optics

Question

A card sheet divided into squares each of size 1 mm² is being viewed at a distance of 9 cm through a magnifying glass (a converging lens of focl length 10 cm) held close to the eye.
What is the angular magnification (magnifying power) of the lens?

Solution

Given,
Least distance of distinct vision, D = -25 cm
Object distance, u = -9 cm

Therefore,

Angular magnification = \frac{D}{u} = \frac{- 25}{- 9} = 2.78