Question

what is relationship between pole and center of curvature ​

Answer 1

Answer:

The distance from the pole to the center of curvature is called (no surprise, I hope) the radius of curvature (r). The distance from the pole to the focal point is called the focal length (f). The focal length of a spherical mirror is then approximately half its radius of curvature.

Answer 2

Answer:

Pole is mid of aperture

Centre of curvature is half of aperture which is part of aperture