Question

An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, the displacement of the image will be 

(a) 30 cm away from the mirror 

(b) 36 cm away from the mirror 

(c) 30 cm towards the mirror 

(d) 36 cm towards the mirror

Answer 1

Correct option  (b) 36 cm away from the mirror 

Explanation:

When object is displaced by 20 cm towards mirror.

So, the image will be shift away from mirror by (60 -24) cm = 36 cm.