Section-C: Comprehension Type
As shown in figure, a thin, flexible wire hangs from point P in a region where there is a uniform, horizontal, magnetic field of magnitude B directed into, and perpendicular to, the plane of the figure. A weight is attached to the bottom of the wire to provide a uniform tension T throughout the wire. (The weight of the wire itself is negligible). When a current I flows from the top to bottom of wire, the wire curves into a circular arc of radius R.
The wire is now removed. A negatively charged particle of charge –q and mass m is launched from the same point P from which the wire was hung, in the same direction as that in which the wire extended from P. If the trajectory of the particle follow the same circular arc as in previous problem the speed of the particle