Physics: Principles with Applications (7th Edition)

Published by Pearson
ISBN 10: 0-32162-592-7
ISBN 13: 978-0-32162-592-2

Chapter 25 - Optical Instruments - General Problems - Page 743: 78

Answer

See answers.

Work Step by Step

a. From Figure 25-20, the length of the telescope is the sum of the focal lengths. $$\mathcal{l}=f_o+f_e=48cm+4.0cm=52cm$$ The magnification is the ratio of the focal lengths (equation 25–3) and the lens with the shorter focal length (4.0 cm) is the eyepiece since we desire the object to be enlarged. Calculate the magnification. $$M=-\frac{f_o}{f_e}=-\frac{48cm}{4.0cm}=-12\times$$ b. Use equation 25–6b to relate the microscope length to other quantities in the problem. $$M=\frac{N\mathcal{l}}{f_ef_o}$$ $$\mathcal{l}=\frac{Mf_ef_o}{N}=\frac{(25)(4.0cm)(48cm)}{25cm}=192cm$$ This is much too long to make a practical microscope.
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.