What is an electromagnet ? Draw a circuit diagram to show how a soft-iron piece can be transformed into an electromagnet .

Explanation

An electromagnet is a magnet in which a magnetic field is produced by an electric current. It generally consists of a core made of magnetic material surrounded by a coil through which an electric current is passed to magnetise the core.
A soft-iron piece can be transformed into an electromagnet by winding insulated copper wire around it [to form a solenoid] and connecting the two ends of the wire to a battery as shown in the figure. The soft-iron piece behaves as a powerful magnet when a current is passed through the solenoid. When the current is switched off, the iron core loses its magnetism and ceases to be an electromagnet . Thus, electromagnets are temporary magnets.