Answer: NIA.
- A NIA
- B NI/A
- C IA/N
- D N/(IA)
Correct answer: A. NIA
Explanation: Magnetic moment m = NIA, directed normal to the coil plane.
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.