Question

1. The distance between the pole and the principal focus of the mirror is
called the​

Answer 1

Answer:

"FOCAL LENGTH" is the name given to the linear distance between the pole and principal focus of a spherical mirror.

Answer 2

Answer:

focal length of that mirror...which is equal to half of the radius for spherical mirrors.

i.e,

$f < focal \: length > = r \div 2$

where,r is radius of spherical mirror or we can say distance of centre of curvature (C) from the pole.