Question

If a spherical mirror is broken into number of pieces , does it effects it's focal length and radius of curvature.

Answer 1

if a spherical mirror is broken into number of pieces: 
1. There will be no change in it's focal length 
2. if there is a change in the radius of the curvature then there will be change in it's focal length, until and unless there is no change in the radius of curvature it doesn't effect the focal length of the spherical mirror. 

Answer 2

if any spherical mirror broken into several number of pieces , no change its radius of curvature .
focal length also will not change because it depends upon radius of curvature .
but intensity of all pieces different and less then initial spherical mirror .