Question

what is the distance PC called?​

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

Explanation:

p means pole of spherical mirror

c means center of curvature of mirror