Answer: magnetisation.
- A magnetisation
- B temperature
- C electric current
- D applied voltage
Correct answer: A. magnetisation
Explanation: In a hysteresis loop, the magnetisation lags the applied field, and the loop area represents energy lost per cycle.
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.