The distance of a real object from the focus of a convex mirror of radius of curvature ‘a’ is ‘b’. Then the distance of the image from the focus is

The focal length of convex mirror is f = a/2The real object distance u = b - a/21v+1u=1f 1v-1b-a/2=2asolving we getv=a2b-a4bdistance of image from focus isa2-v=a24b