A convex lens of focal length 4.0 cm is used as a hand-held reading glass.
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A convex lens of focal length 4.0 cm is used as a hand-held reading glass.
(i) Calculate its magnifying power when the reader adjusts the lens so that the virtual image is formed at the near point situated 25 cm from the eye.
(ii) Calculate the magnifying power if, instead, the lens is adjusted so that the final image is at infinity (normal vision).
(iii) Determine the percentage increase in magnifying power obtained by shifting from normal-vision adjustment to near-point adjustment.