You are looking at your face at a distance of 20 cm in front of a concave mirror with a focal length of 30 cm. What is the size of the image of your face compared to its real size?
A)half as large
B)1.5 times larger
C)2 times larger
D)3 times larger

Question

Quizplus · Accepted Answer

The mirror formula is 1/f = 1/v + 1/u. Given f = -30 cm (concave mirror) and u = -20 cm (object distance), solving gives v = -60 cm. The magnification is -v/u = 60/20 = 3, so the image is 3 times larger.

You Are Looking at Your Face at a Distance of 20