question_answer

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is [AIPMT (M) 2012]

A)  10 cm

B)       15 cm

C)  2.5 cm

D)       5 cm

Correct Answer: D

Solution :

By mirror formula, image distance of A

Also image distance of C

The length of image