To distinguish between a plane mirror, a convex mirror and a concave mirror, the given mirror is held near the face and the image is seen.
- If the image is upright, of same size as the object and it does not change in size when the mirror is moved, then the mirror is a plane mirror.
- If the image is upright, magnified and it becomes inverted when the mirror is moved away from the face, then the mirror is a concave mirror.
- If the image is upright and diminished and it remains upright when the mirror is moved away from the face, then the mirror is a convex mirror.