An image in a convex lens is upright and magnified 3 times. If the focal length of the lens is 15 cm, what is the object distance?
-
A.
10 cm -
B.
25 cm -
C.
16 cm -
D.
14 cm
Correct Answer: Option A
Explanation
m = v/u = -3
v = -3u
f = 15cm1/v + 1/U = 1/f1/-3U + 1/u = 1/152/3u = 1/15
3U = 15 x 2
U = 30/3
= 10 cm