Reflection of Light

The use of a concave mirror depends upon the distance of the object from the mirror. Some of the uses are listed below.

Uses of Concave Mirrors

Concave mirrors are used for the following purposes:

As reflectors in the head lights of cars, search lights in torches etc. to obtain a parallel beam of light. For this, the source of light is placed at the focus of the concave reflector.
By dentist to focus light on the tooth to be examined.
As shaving mirrors and as make up mirrors to get an enlarged erect image of the face
To concentrate solar radiations in solar heating devices. For this the food or substance that has to be heated is placed at the focus of a large concave reflector. After reflection, sun light converges on the substance and heats it.

The following table gives the position, size and nature of the image formed in a concave mirror corresponding to different positions of the object and the use of concave mirror.

Position of the object	Position of the image	Nature and size of the image	Use
At infinity	At the focus	Real, inverted and diminished	Used by ENT surgeons and dentists
Beyond the centre of curvature	Between the focus and the centre of curvature	Real, inverted and diminished	Used in solar cookers
At the centre of curvature	At centre of curvature	Real, inverted and same size as object	Used as an erecting mirror in terrestrial telescopes
Between the focus and centre of curvature	Beyond the centre of curvature	Real, inverted and magnified	Used in hospitals and clinics to see the internal parts of the body
At focus	At infinity	Real, inverted and magnified	Used in search lights and in head lights of motor cars
Between the pole of the mirror and the focus	Appears behind the mirror	Virtual, erect and magnified	Used as a shaving mirror