Spherical Mirror- A mirror which is made from a part of a hollow sphere.
Concave mirror- A mirror which is polished from the bulging side of a hollow sphere , such that the reflecting side is towards its hollow side.
Convex mirror- A mirror which is polished from the hollow side of the sphere, such that reflecting surface is towards its bulging side.
-The mid point of the spherical mirror is called Pole .It is denoted by the symbol P
Center of curvature
The center of th :e sphere of which the spherical mirror is a part is called center of curvature and is denoted by symbol C.
Principal Axis- An imaginary line passing through the pole and the centre of curvature of a spherical mirror is called principal axis.
Linear Aperture- The diameter of a spherical mirror is called linear aperture.
Principal Focus-It is a point on the principal axis where a beam of light parallel to the principal axis , after reflection either actually meets or appear to meet. It is denoted by the letter F.
Focal length - The linear distance between the pole and the principal focus is called focal length. It is denoted by the letter f.
Radius of curvature-The linear distance between the pole and centre of curvature is called radius of curvature.It is denoted by the letter R.

centre of curvature and pole