Question

An image of am object is observed on a plane mirror. The distance between the mirror and the imageis15cm. If the pencil is moved 3cm towards the mirror then what would be the distance between image and the objects

Answer 1

In the first condition the distance was 15 cm.
Now, the distance is decreasd from 3 cm.
So, 15-3 = 12cm.
Now the distance b/w the object and mirror is 12 cm
Hence the distance between object and image will be 12 + 12 = 24 cm.

Answer 2

okay so the distance between the pencil image and the plane mirror is 15 cm so the total distance between the image formed and the real object should be 30 cm. understand.

now the pencil is moved 3 cm from the mirror so its image should also move 3 cm. okay

so the distance= distance at starting-distance at the end

                         = 30-6

                         = 24 cm

if you have any doubt than you can ask