Calculate the position of an object placed in front of a convex mirror having focal length of 12cm such that an image is formed 6 cm away from the mirror?

A. 4. 0 cm
B. 3. 0 cm
C. 12.0 cm
D. 9.0 cm

Correct Answer:

Option C = 12.0 cm

Explanation

f = -12 cm, v = – 6 cm
(1)/v + (1)/u =(1)/f
(1)/-6 + (1)/u = (1)/-12
(1)/u = (1)/-12 + (1)/6 = (1 + 2)/12 = (1)/12
∴ u = 12 cm