Consider a solar thermal “power tower” with a central tower of height 60 m, surrounded by an array of planar mirrors on the ground extending to a radius of 100 m around the tower. At the top of the tower there is a cylindrical absorber with its axis aligned vertically. Each mirror is large enough so that the complete reflection of the Sun can be seen on each mirror from the center of the tower at the height of the absorber. 

(a) Give an upper limit on the number of mirrors that could be placed around the tower subject to these constraints.

(b) How wide does the absorber have to be so that light rays coming from the center of the Sun hit the absorber, no matter which point on which mirror they are reflected from?