alleryAn electromagnet differs from a permanent magnet because it
AIs always weaker than any natural magnet
BActs as a magnet only while current flows
CHas its poles fixed and never reversible
DWorks only inside a vacuum tube
Answer & Solution
Correct answer: B. Acts as a magnet only while current flows
1. The chapter compares electromagnets with bar magnets.
2. An electromagnet's field exists only while current is on.
3. Reverse the current and the poles flip.
4. A permanent magnet keeps its poles always.
_Source: Selina Concise Physics Class 10, Ch 10 Electromagnetism (Mistral OCR'd PDF), section on electromagnet vs permanent magnet_
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