A mirror is a reflective surface through which light does not pass through, but bounces off and produces an image. There are two major types of mirrors. One is the flat plane mirror, and the other is a curved or spherical mirror. A mirror with a flat surface is called a plane mirror, and a mirror with a curved surface is called a spherical mirror.

Image is a visual representation of an object which is placed somewhere in front of or behind a mirror or lens. When an object is placed in front of a mirror, its image is seen in the mirror. The object is the source of the incident rays and the image is formed by the reflected rays. Based on the intersection of light rays, the images are classified as either (a) a real image or a virtual image, (b) erect image or inverted image, (c) magnified, diminished or the same size as the object image.