PHYSICS · Single correct · AP · Physics 2: Algebra-based · Geometric Optics · Geometric Optics
Problem
While shaving, a person holds his face 15 cm in front of a mirror and sees an erect image that is twice the size of his face. Calculate the focal length of the mirror.
(a) −10cm
(b) +10cm
(c) −30cm
(d) −7.5cm