The diagram shows a small bead of mass m carrying charge q. The bead can freely ring placed on a smooth fixed ring placed on a smooth horizontal plane. In the same plane a charge `+Q` has also been fixed as shown. The potential at the point P due to `+Q` is V. The velocity with which the bead should projected from the point P so that is can complete a circle should be greater than

Answer

A

Explanation

Given `V_(A)` due to `+Q` is V, so `V_(B)=4V`
By energy conservation
`1/2 m u^(2)+qV=4qV`
`rArr u=sqrt((6qV)/m)`