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

(N/A) To obtain a permanent magnet using a current-carrying solenoid,the following conditions must be met:
$(i)$ The core material placed inside the solenoid must be a magnetically hard material,such as steel,which retains its magnetism even after the current is switched off.
(ii) $A$ direct current $(DC)$ must be passed through the solenoid to magnetize the core material effectively.
(iii) Once the steel rod is placed inside the solenoid and the current is passed,it becomes a permanent magnet.