Question

State four ways of measuring the strength of an electromagnet.

Answer 1

The strength of an electromagnet is estimated from the magnetic effect it produces. Four ways of increasing its strength are:

1. Increasing the number of turns of the coil wound on the soft iron core.
2. Increasing the current flowing through the coil.
3. Using a soft iron core inside the coil, as it becomes magnetised and intensifies the magnetic field.
4. Using a laminated soft iron core made of thin insulated sheets/wires, which reduces eddy-current losses and makes the field stronger. If 'measuring' is taken literally, the strength can be compared by counting the number of iron pins attracted, by noting the deflection of a magnetic compass needle, by using a spring balance to measure the pull on a soft iron piece, or by observing the induced current in a small search coil connected to a galvanometer.