Question

A small charged ball of mass m and charge q is suspended from the highest point of a ring of radius r by means of an insulated cord of negligible mass. The ring is made of a rigid wire of negligible cross section and lies in a vertical plane. On the ring, there is uniformly distributed charge q of the same sign as that of q. Determine the length of the cord so as the equilibrium position of the ball lies on the symmetry axis, perpendicular to the plane of the ring. (a) ( 2kqqr mg ) 13 (b) ( kqqr mg ) 13 (c) ( kqqr 2mg ) 13 (d) ( kqqr mg ) 3

Answer 1

i hope this will help you. i am giving answer with the help of one numerical.