Acurrent‑carrying wire lies in a region where there is an external magnetic field, but there is no magnetic force acting on the wire. how can this be?
a) the length of the wire is oriented either parallel or antiparallel to the magnetic field lines at the location of the wire
b) the current is carried by equal numbers of positive and negative charges that flow in opposite directions along the wire
c) the magnetic field is generated by a second wire carrying a current in the opposite direction