An object is placed near a concave mirror having a radius of curvature of magnitude 60 cm.How far should you place the object from the mirror so that the lateral magnification produced by the mirror will be +2.5?
A)18 cm
B)24 cm
C)30 cm
D)36 cm
E)42 cm

Question

Quizplus · Accepted Answer

The lateral magnification of a concave mirror is given by the equation m = -v/u, where v is the image distance and u is the object distance. If the lateral magnification is +2.5, then v = -2.5u. The radius of curvature of the mirror is R = 60 cm, so the focal length is f = R/2 = 30 cm. Using the thin lens equation, 1/f = 1/v + 1/u, we can solve for u:1/30 = 1/-2.5u + 1/u1/30 = -1/2.5u + 1/u1/30 = 1/2.5u - 1/u1/30 = -1.5/2.5uu = -18 cmTherefore, the object should be placed 18 cm from the mirror.

An Object Is Placed near a Concave Mirror Having a Radius