AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
(C) Loses its magnetism easily when current is switched off
Soft iron is used as the core of an electromagnet because it loses its magnetism easily when the current is switched off, making it a temporary magnet — ideal for electromagnets.
The textbook states that an electromagnet consists of a core of soft iron wrapped with insulated copper wire. The key property is that soft iron is easily magnetised and demagnetised — when current stops, the magnetic field disappears. Steel retains magnetism and would become a permanent magnet, which is undesirable for an electromagnet. Options A and D are irrelevant to magnetism; Option B (resistance) has nothing to do with core material selection.
Source: Chapter 12, "What you have learnt" / Section 12.2.4