Convex Mirror

Definition: What is Convex Mirror?

A convex mirror is a curved mirror that forms a part of a sphere and designed in such a way that light falling on its shiny surface diverges upon reflection. Hence, it is also called a diverging mirror. It cannot be used to produce real images. The image produced by a convex mirror is called a virtual image. It is formed behind the mirror, upright, and diminished but increases in size up to the object size as the object approaches closer to the mirror. This virtual image is created by extending the reflected rays backward.

Ray Diagram for Convex Mirror

Terms Used in Convex 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 convex mirror has been constructed
Radius of curvature – The radius of the sphere from which the convex mirror has been constructed
Pole – The mid-point of the convex 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 appear to diverge from
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 Convex Mirrors

As side view mirrors in cars, buses, and trucks because the image formed is upright and small thus giving a wide field of view of the area toward the side of and behind the vehicle
As a security device in supermarkets, grocery stores, and convenient stores since the convex mirror gives a broad view of the area around corners
At corners on a road so that drivers can see the incoming vehicles and avoid a collision
As a safety device in warehouses, where workers can see incoming forklifts and vehicles
As security device in ATM since the user can see the area behind them
As street light reflectors because the reflected light can spread over a large area

Difference between Convex Mirror and Concave Mirror

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