If the focal length of a spherical mirror is 12.5 less cm, what will be its radius of curvature? 

As we know Radius of the curvature of a spherical mirror = 2 times of focal length

 Radius of the curvature the spherical mirror
             = 2 ×12.5 cm.

So  Radius of the curvature of the spherical mirror
              = 25 cm.