A concave spherical mirror has a focal length of magnitude 20 cm. An object is placed 30 cm in front of the mirror on the mirror's axis. Where is the image located?
A) 12 cm behind the mirror
B) 60 cm behind the mirror
C) 12 cm in front of the mirror
D) 60 cm in front of the mirror

Question

Quizplus · Accepted Answer

Using the mirror equation 1/f = 1/do + 1/di, where f is the focal length (-20 cm for concave), do is the object distance (30 cm), and di is the image distance. Solving gives di = 60 cm in front of the mirror.

A Concave Spherical Mirror Has a Focal Length of Magnitude