The diagram show a small bead of mass `m` carrying charge `q`. The bead can freely move on the smooth fixed ring placed on a smooth horizontal plane . In the same pane a charge ` +Q` has also been fixed as shown. The potential at the point ` P` due to ` +Q` is `V` . The velocity which the bead should projected from the point `P` so that it 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)`