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An electromagnet differs from a permanent magnet in that the electromagnet:
AIs always weaker
BLoses its magnetism when current is switched off
CHas only one pole
DCannot attract iron
Answer & Solution
Correct answer: B. Loses its magnetism when current is switched off
1. An electromagnet is a soft-iron core inside a current-carrying coil.
2. Soft iron is easily magnetised but loses magnetism quickly when current stops.
3. Hence electromagnets can be turned ON/OFF — useful in cranes, electric bells, relays.
4. Permanent magnets (e.g., steel) retain magnetism on their own.
_Source: NCERT Class 10 Science Ch 12 §12.3 Electromagnet_
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