- A curve is part of a circle. Therefore
- the centre of the circle will also be the centre of the curve and is called the centre of curvature, and
- the radius of the circle will be equal to the radius of the curve, called the curvature radius.
|Centre of curvature, C
|The geometric centre of a hollow sphere of which the concave or convex mirror is a part.
|Pole of mirror, P
|The centre point on the curved mirror.
|A line which passes through the centre of curvature, C and the pole of a curved mirror, P.
|Radius of curvature, r
|Distance between the pole, P and the centre of curvature, C.
|Principal focus, F
|A point through which all rays travelling parallel to the principal axis converge to or appear to diverge from after reflection by the mirror.
|Focal length, f
|The distance between the principal focus, F and the pole of the
curved mirror, P.
|Aperture of mirror
|The portion of the surface of the mirror that reflects light.
|Object distance, u
|Distance of object from the pole of the mirror, P.
|Image distance, v
|Distance of image from the pole of the mirror,