Figure shows a wire sliding on two parallel, condu cting rails placed at a separation l. A magnetic field B exicts in a direction perpendicular to the plane of the rails. What force is necessary to keep the wire moving at a constant velocity v ?
This force produces an acceleration of the wire.
Since the velocity is given to be constant.
Hence net force acting on the wire must be zero.
A straight wire of length l can slide on two parallel plastic rails kept in a horizontal plane with a separation d. The coefficient of friction between the wire and the rails is μ. If the wire carries a current i, what minimum magnetic field should exist in the space in order to slide the wire on the rails.