Question

Under what conditions permanent electromagnet is obtained if a current carrying solenoid is used? Support your answer with the help of a labelled circuit diagram.

Answer 1

The following conditions are required to obtain permanent electromagnet when a current-carrying solenoid is used :

1.  Rod inside the solenoid should be made of a magnetic material like steel which should retain magnetic properties for a long time after magnetization.
2. The current through the solenoid should be direct current.
3. The number of turns in the solenoid should be large and closely packed so that a strong uniform magnetic field inside it is produced.