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 .

Options

A. `sqrt((6qV)/m)`
B. `sqrt((qV)/m)`
C. `sqrt((3qV)/m)`
D. None of these

Answer

A

Explanation

`V_p=(KQ)/(4a)=V`
COE `q((KQ)/a)+0=q ((KQ)/(4a))+1/2 mv^2, 3q ((KQ)/(4a0))=1/2 mv^2 implies V=sqrt((6qv)/m)`