The focal length of a convex mirror is -20 cm. What is its radius of curvature?
A) -10 cm
B) 40 cm
C) -40 cm
D) -20 cm
E) 20 cm

Question

Quizplus · Accepted Answer

For a convex mirror, the focal length (f) is half the radius of curvature (R). So, we have:
f = -20 cm
R = -2f = -2(-20 cm) = 40 cm
Remember that the sign convention for mirrors is such that a negative radius of curvature means the mirror is convex. Therefore, the correct answer is (C) -40 cm.

The Focal Length of a Convex Mirror Is -20 Cm