Question

in a trick mirror, head appears smaller than the rest of the body why

Answer 1

The type of image that is formed in a mirror is dependent on the reflecting surface the mirror has. If the mirror has the plane reflecting surface the image formed will be of the same size as that of the object .
If we stand in front of a mirror that is bulged outwards and the mirror bent at top and bottom , our image will be of small size and we will look fatty. Whereas , if we look in a mirror that is bulged out and bent at sides our image appears thin.