Question

The north south polarities of an electromagnet can be found easily by using:

Answer 1

Hint:An electromagnet is a magnet whose magnetic field is produced by an electric current. Wire wound into a coil is used to make electromagnets. A current flowing through the wire produces a magnetic field that is centred in the opening, which marks the coil's centre.

Complete answer:
The current position determines the polarity of the electromagnet. Using the right hand, determine the electromagnet's north pole. Wrap our fingertips around the coil in the opposite direction of the current. The magnetic field travels in the same direction as our thumb, so north will emerge from the electromagnet in the same direction as our thumb.The clock face law can be also used to determine the north and south polarities of an electromagnet.

When we look at one face of a circular wire (or coil) through which a current is flowing according to the clock face law:
-If the current runs clockwise around the face of the circular wire (or coil), the face of the circular wire will be the South pole ( S-pole).
-If the current flowing through the face of the circular wire (or coil) is going in the opposite direction, the face would be the North pole ( N-pole).

Note: The electromagnet will change its flux density when the current fluctuates when attached to an AC voltage or current source. As the current reverses direction after half second, the polarity of the magnet will also shift. As compared to a DC voltage, the AC current that would naturally flow is decreased due to the electromagnet's inductance.