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 is:

• A. 8 m
• B. 6 m
• C. 4 m
• D. 2 m

Answer 1

The correct option is A 8 m

In a plane mirror, distance between the object and the mirror $\left(D_o\right)$ is equal to the distance between the image and the mirror $\left(D_i\right)$.
It is given that, $D_i=$ $6m$
$\therefore D_o$ $=6m$.
When the boy moves $2m$ towards the mirror, the distance between the boy and the mirror, $D_o^{\prime }=6-2=4m$
Let the distance between the mirror and the image in the second situation be $D_i^{\prime }=D_o^{\prime }=4m$
$\therefore$ the distance between the boy and his image $D_o^{\prime }+D_i^{\prime }=4+4=8m$