College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 65

A laboratory (astronomical) telescope is used to view a scale that is 300 cm from the objective, which has a focal length of 20.0 cm; the eyepiece has a focal length of 2.00 cm. Calculate the angular magnification when the telescope is adjusted for minimum eyestrain. Note: The object is not at infinity, so the simple expression m = f o / f e is not sufficiently accurate for this problem. Also, assume small angles, so that tan .