Question

Quite often, connecting wires carrying currents in opposite directions are twisted together in using electrical appliances. Explain how it avoids unwanted magnetic fields.

Answer 1

Explanation:

• In the electrical appliances, the connecting wires that carry current in opposite directions are together twisted.
• The resultant fields from the consecutive twists can be observed in the opposite directions when the wire is twisted. Thus, the cumulative effect is roughly zero over the long length of the wire.
• In between the two wires B1 and B2, let any point be the magnetic field, which is because of wire 1 and wire 2.
• It is observed from the figure that due to first turn, the net magnetic field is into the paper. Because of the second turn that is twisted, it is out on the paper plane, which leads to the cancellation of these fields.
• So, when there is a twisted wire, then from the consecutive twists, the resultant fields appear in the opposite directions. Hence, over a long lengthy wire, the cumulative effect is roughly zero.