Answer: ampere-metre (A·m).
- A ampere-metre (A·m)
- B the tesla unit (T)
- C the weber unit (Wb)
- D the henry unit (H)
Correct answer: A. ampere-metre (A·m)
Explanation: Pole strength is measured in ampere-metre (A·m).
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.