Solution:
It is necessary to meet the following conditions in order to obtain a permanent electromagnet from a current-carrying solenoid.
Soft iron is used in a closed-circuit core.
Under what conditions permanent electromagnet is obtained if a current-carrying solenoid is used? Support your answer with the help of a labeled circuit diagram.
Under what conditions permanent electromagnet is obtained if a current-carrying solenoid is used? Support your answer with the help of a labeled circuit diagram.