When the coil is connected to an a.c. circuit, an a.c. current is also induced in the ring, acting at any given moment in the opposite direction to that in the coil, since the ohmic resistance of the ring is very low. The magnetic fields caused by currents flowing in opposite directions react on one another and seek to repel from each other the wires along which these currents are flowing. As a result of the fact that currents flowing in opposite directions repel each other, the ring jumps up. When the coil is connected to a d.c. circuit, the ring will jump away at the moment of connection as a result of the appearance of an induced current acting in the opposite direction.