When a person stands 40 cm in front of a cosmetic (concave) spherical mirror, the upright image is twice the size of the object. What is the focal length of the mirror?
A) 80 cm
B) 40 cm
C) 27 cm
D) 160 cm

Question

Quizplus · Accepted Answer

The magnification is -2 (since the image is upright and virtual), and using the mirror formula and magnification formula, we find the focal length to be 80 cm.

When a Person Stands 40 Cm in Front of a Cosmetic