College Physics (7th Edition)

Published by Pearson
ISBN 10: 0-32160-183-1
ISBN 13: 978-0-32160-183-4

Chapter 25 - Vision and Optical Instruments - Learning Path Questions and Exercises - Exercises - Page 871: 14


Power of top half of the lens is $-0.2D$ and that of the lower half is $+2.57D$

Work Step by Step

The doctor recommended bifocal lenses. For upper half :- $P_{upper}=\frac{1}{f}=\frac{1}{do}+\frac{1}{di}=\frac{1}{infinity}+\frac{1}{-5}=-0.2D$ For lower half :- $P_{lower}=\frac{1}{f}=\frac{1}{do}+\frac{1}{di}=\frac{1}{0.25}+\frac{1}{-0.7}=+2.57D$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.