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 - Problems - Page 741: 36

Answer

$M=+18$

Work Step by Step

See Figure 25-20. When the object and the image are both far away, the separation of the 2 lenses is the sum of their focal lengths. The Galilean telescope is discussed on page 725. It uses a diverging lens as an eyepiece and forms upright, virtual images. $$L=f_o+f_e$$ $$ f_e =L-f_o =36.8-39.0cm=-2.2cm$$ As expected, the diverging lens, the eyepiece, has a negative focal length. Use equation 25-3 to find the magnification of the telescope. $$M=-\frac{f_o}{f_e}=-\frac{39.0cm}{-2.2cm}\approx+18$$ As expected, the positive magnification means that the image is upright.
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.