A concave mirror has a focal length of 20 cm.What is the magnification if the object and image distances are 10 cm and -20 cm respectively?
A)1
B)2
C)1/2
D)1/4
E)-1/2

Question

Quizplus · Accepted Answer

The magnification (m) is given by the formula m = - (image distance) / (object distance). Here, the image distance is 20 cm and the object distance is 10 cm, so m = - (20 cm) / (10 cm) = -2. The negative sign indicates that the image is inverted.

A Concave Mirror Has a Focal Length of 20 Cm