An object is placed 5 cm from the pole of a concave mirror. if the focal length of the mirror is 10 cm. what is the image distance?
-
A.
10 cm in front of the mirror. -
B.
5 cm in front of the mirror -
C.
10 cm behind the mirror -
D.
5 cm behind the mirror
Correct Answer: Option C
Explanation
u = 5 cm , f = 10 cm, v = ?
(1)/v + (1)/u = (1)/f
(1)/v + (1)/5 = (1)/10
= (1)/v = (1)/10 = (1)/5 = (1 – 2)/10 = (1)/10
∴ v = – 10 cm
∴ The image is 10 cm behind the mirror