An object is held at a distance of 18 cm from a convex mirror creating an image that is 1/6 the object size.What is the focal length of the mirror?
A) −3.6 cm
B) −18 cm
C) −6.0 cm
D) −9.0 cm

Question

Quizplus · Accepted Answer

The image is 1/6 the object size, so the magnification is 1/6. The magnification equation for a convex mirror is:1/f = 1/p + 1/qwhere f is the focal length, p is the object distance, and q is the image distance.Substituting the given values into the equation, we get:1/f = 1/18 + 1/(-6)1/f = 1/9f = -9 cmTherefore, the focal length of the mirror is -9 cm.

An Object Is Held at a Distance of 18 Cm