(a) A boy with a mouth 5 cm wide stands 2 m away from a plane mirror. Where is his image and how wide is the image of his mouth?
(b) The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?

(a) The image formed is 2m behind the mirror and 5 cm wide. The reason being, a plane mirror forms an image of the same size as the object, and at the same distance behind the mirror as that of the object from the mirror.
(b) The image approaches him at a speed of 2 m/s . The reason being, the image moves at a speed of 1 m/s and
the relative speed of the image will be equal to the sum of the speeds of the image and the boy.