An object of heights 5 cm is placed at 20 cm from a concave mirror of focal length 10 cm. the image height is?
A
20 cm
B
15 cm
C
10 cm
D
5 cm
Verified Correct Answer: D.
Physical Principles & Numerical Solution
(1)/V + (1)/U = (1)/f
(1)/V + (1)/20 = (1)/10
(1)/V = (1)/10 - (1)/20 = (2 -1)/20 = (1)/20
∴ V = 20 cm
mag = (image height)/object height = (v)/u
(X)/5 = (20)/50
X = 5 cm
Source: WAEC / JAMB / NECO Classroom Archive (Record #14049)