| 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. |
| Principal axis |
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, |
