A woman looking in a makeup mirror sees her face at twice its actual size and right-side up.If she is 22.0 cm from the mirror,what is its focal length?

Question

Quizplus · Accepted Answer

The magnification (m) is +2, indicating a virtual, upright image. For mirrors, m = -q/p, where q is the image distance and p is the object distance. Here, m = 2 = -q/22 cm, so q = -44 cm (virtual image). Using the mirror equation 1/f = 1/p + 1/q, we get 1/f = 1/22 - 1/44, which gives f = 44 cm.

A Woman Looking in a Makeup Mirror Sees Her Face