When a point source of light is placed in front of a plane mirror, rays of light from the source fall on the mirror and are reflected back. These rays, after reflection, enter the eye, and appear to emanate from a point behind the mirror. The eye sees the image of the source at this point. Since the light rays do not actually come from this point, the image is called a virtual image. A virtual image cannot be taken on a screen. A real image on the other hand, is formed by the actual intersection of rays and can be taken on a screen. An image formed in a plane mirror has the following characteristics – (I) The image is of the same size as the object. (II) It is as far behind the mirror as the object is in front of it. (III) It is virtual. (IV) It is laterally inverted, i.e. If a person is wearing a watch on his left hand, the watch appears to be on right hand of the image.