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

Initially, the boy is at B1. 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 2 m towards the mirror, the image will shift to the position B2' as shown in the figure. Now the distance from the mirror to B2 is 4m and the distance from the mirror to B2' is 4m. And hence, the distance between the boy and his image becomes equal to 8 m, as evident from the figure below.