Concave Mirror

Definition: What is Concave Mirror?

A concave mirror is a curved mirror that forms a part of a sphere and designed in such a way that rays of light falling on its shiny surface converge upon reflection. Hence, it is also called a converging mirror. A concave mirror produces both real and virtual images, which can be upright or inverted. The size of the image can be bigger or smaller than the object. The nature, size, and position of the image depend on the position of the object.

Ray Diagram for Concave Mirror

Terms Used in Concave Mirror Imaging

Incident ray – The ray of light that is incident on the surface
Reflected ray – The ray of light that is reflected from the surface
Center of curvature – The center of the sphere from which the concave mirror has been constructed
Radius of curvature – The radius of the sphere from which the concave mirror has been constructed
Pole – The mid-point of the concave mirror
Principal axis – An imaginary line that connects the pole and the center of curvature
Focus – A point on the principal axis where rays of light that are parallel to the axis converges after reflection
Focal length – The distance between the pole and the focus and is one-half of the radius of curvature
Object distance – The distance between the object and the pole
Image distance – The distance between the image and the pole

Applications of Concave Mirror

In torchlight, headlamp, vehicle headlight, searchlight, and lighthouse, where a beam of light is converged to a certain point thus giving a better focus
As vanity mirrors for facial makeup and as shaving mirrors for shaving
In solar ovens to collect an enormous amount of solar energy and concentrate it at a point for heating and cooking
By dentist to examine teeth and ENT specialist to observe a magnified image of the ear canal
In an electron microscope, astronomical telescope, and visual bomb detectors

Difference between Concave Mirror and Convex Mirror

Concave Mirror vs. Convex Mirror
Property	Concave Mirror	Convex Mirror
Other names	Converging mirror	Diverging mirror, fish-eye mirror
Reflecting surface	Curved inwards	Curved outwards
Center of curvature	Lies on the same side of the reflecting surface	Lies on the opposite side of the reflecting surface
Focus and focal length	Lies in front of the mirror and focal length is positive	Lies behind the mirror and focal length is negative
Image	Real and inverted, except when the object is placed between the pole and the focus. In that case, the image is virtual, upright, and enlarged.	Virtual, upright, and diminished
Image size	Can be smaller, equal to, and bigger than the object depending on the position of the object	Smaller than the size of the object
Image position	Can be anywhere on principle axis depending on the position of the object	Always within the focus
Image projection	Only real image can be projected on a screen	Cannot be projected on a screen
Uses and applications	Reflecting telescope, headlamp, searchlight, and torchlight	Side view mirrors in vehicles and as security mirrors in grocery stores and supermarkets