A convex lens of short focal length is often used as a reading glass.
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A convex lens of short focal length is often used as a reading glass.
(i) Define least distance of distinct vision for a normal human eye.
(ii) Explain, with the help of the idea of angular size, how placing an object within the focal length of such a lens allows the eye to see a magnified, virtual image at infinity while the eye remains relaxed.
(iii) Giving suitable reasoning (without using a mathematical derivation), state why lenses of smaller focal length provide larger magnifying power under this viewing condition.