If a wire had a current which was continually reversing directions and hten was placed between the poles of a magnet what would happen to the force on the wire?

Answer 1

Draw an imaginary line between the poles of a horseshoe magnet, say horizontal. If the wire is along that line there will be no magnetic force on it because the current would be parallel /antiparallel to the magnetic field. If the wire is perpendicular to the line, say vertical, the magnetic force on the wire will be in then out. If the wire is perpendicular ,say in/out, then the magnetic force will be vertical up then down. That's what the magnetic force would be, It changes direction when the current changes direction. To actually see the effect however could be difficult because; the wire has to be part of a circuit which could cause problems giving it enough "freedom" to move. If you use household current, which changes direction every 1/120 th of a second, the wire will not have time to move very far before the force changes directions and its doubtful you will be able to see the motion. Finally even if the current changed more slowly you still need a pretty strong current (a few amps) and a pretty strong magnet to see the effect.

Answer 2

The force would change direction repeatedly. The force on a wire with a current in a magnetic field depends on the direction of the current. When the current is in one direction, the force would act downward. When the current is in the opposite direction, the force on the wire would act upward.