Answer: easily magnetised and demagnetised.
- A easily magnetised and demagnetised
- B able to retain magnetism forever
- C impossible to magnetise
- D strongly diamagnetic
Correct answer: A. easily magnetised and demagnetised
Explanation: Soft iron magnetises and demagnetises readily, ideal for temporary electromagnets.
Magnetic field lines form closed loops: outside the bar magnet they run from the N pole to the S pole; inside, they continue from S back to N, so the lines never start or end anywhere.
Concept context
Bar magnets, Earth's magnetism, and how different materials respond to an external magnetic field - diamagnetic, paramagnetic, and ferromagnetic behaviour.