A conducting sphere S1 of radius r is attached to an insulating handle. Another conducting sphere S2 of radius R(>r) is mounted on an insulating stand, S2 is initially uncharged. S1 is given a charge Q . Brought into contact with S2 and removed. S1 is recharged such that the charge on it is again Q and it is again brought into contact with S2 and removed. This procedure is repeated n times.
(a) Find the electrostatic energy of S2 after n such contacts with S1 .
(b) What is the limiting value of this energy as n→∞ ?