Question

An object is placed at a distance of 10 cm from a plane mirror. If the object is moved 4 cm

toward mirror, the relative change of distance of object and its image is :​

Answer 1

In a plane mirror, we know that the distance between the object and the  mirror and the distance between the image and the mirror is always the same.

So, if the object is at 10 cm from a mirror, then the distance between the object and the its image is 10×2=20cm.

The object is brought 4cm close to the mirror. Now, the distance between the object and the mirror is 10-4=6cm and distance between the object and its image is 6×2=12cm.

So, change in the distance between the object and its image is 20-12=8cm nearer.