What is a Concave Mirror?

A concave mirror is a spherical mirror that curves inward, resembling a portion of the inner surface of a sphere. It reflects light inward to a single focal point, making it useful for focusing light.

The key formula for concave mirrors, also known as the mirror formula, is 1/f = 1/v + 1/u

where: f: is the focal length of the mirror, u: is the object distance (distance from the object to the mirror), v: is the image distance (distance from the image to the mirror).

The magnification (m) of a concave mirror can be calculated using two main formulas:

m = h'/h or m = -v/u

where h' is the image height, h is the object height, v is the image distance, and u is the object distance.

Ray Diagrams

Ray diagrams help to understand how light behaves when it strikes a concave mirror.

Image Characteristics

Object Position	Image Position	Image Nature	Image Size
Beyond Center of Curvature (C)	Between F and C	Real and Inverted	Smaller
At Center of Curvature (C)	At C	Real and Inverted	Same Size
Between C and Focus (F)	Beyond C	Real and Inverted	Larger
At Focus (F)	At Infinity	Real and Inverted	Highly Enlarged
Between Focus (F) and Pole (P)	Behind Mirror	Virtual and Erect	Larger

Uses of Concave Mirrors

Application	Reason for Use
Shaving Mirrors	Enlarges image of the face
Solar Furnaces	Concentrates sunlight at one point
Telescope Mirrors	Focuses distant light to a point
Ophthalmoscopes	To focus light into the eye
Headlights of Vehicles	Focuses light into a beam

What is a Convex Mirror?

A convex mirror is a spherical mirror that curves outward. It reflects light outwards and diverges rays, so they appear to come from a common point behind the mirror. It always forms a virtual, upright, and diminished image.

The mirror formula for a convex mirror is : "1/f = 1/u + 1/v"

where 'f' is the focal length,

'u' is the object distance,

and 'v' is the image distance.

The magnification formula for a convex mirror, like all spherical mirrors, is

m = -di/do or -v/u

where 'm' is the magnification, 'di' is the image distance, and 'do' is the object distance.

Ray Diagrams

Ray diagrams for convex mirrors show how the reflected rays diverge and seem to come from a point behind the mirror.

Image Characteristics

Object Position	Image Position	Image Nature	Image Size
Anywhere between P and infinity	Behind the mirror between P and Focus	Virtual and Erect	Diminished
At Infinity	Behind the mirror at Focus	Virtual and Erect	Diminished

Uses of Convex Mirrors

Application	Reason for Use
Rear-view Mirrors in Vehicles	Provides a wide field of view
Security and Surveillance	Used in stores or hallways to see around corners
Road Safety Mirrors	Helps drivers at blind turns or parking lots
ATMs and Elevators	To see surroundings for security