Question

A boy is observing his image in a plane mirror. The distance between the mirror and his image is $6m$. If he moves $2m$ towards the mirror, then the distance between the boy and his image will be:

• A. 8 m
• B. 6 m
• C. 4 m
• D. 2 m

Answer 1

The correct option is A 8 m

Initially, the boy is at $B_1$. In a plane mirror, the image is the same distance behind the mirror as the object is in front of the mirror. When he moves $2m$ towards the mirror, the image will shift to the position $B_2^{\prime }$ as shown in the figure. Now the distance from the mirror to $B_2$ is $4m$ and the distance from the mirror to$B_2^{\prime }$ is $4m$. And hence, the distance between the boy and his image becomes equal to $8m$, as evident from the figure below.