Answer: Energy dissipated as heat per unit volume of the material in one cycle.
- A The maximum magnetic field reached inside the material
- B Energy dissipated as heat per unit volume of the material in one cycle
- C The retentivity of the material in that one cycle
- D The total magnetic flux passing through the material in one cycle
Correct answer: B. Energy dissipated as heat per unit volume of the material in one cycle
Explanation: The area of the hysteresis loop equals the energy lost as heat per unit volume of the material during one cycle of magnetisation, which is why transformer cores use materials with a small loop area.
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.