Answer: 2:1.
- A 2:1
- B 1:2
- C 1:1
- D 4:1
Correct answer: A. 2:1
Explanation: For a short dipole, the axial field is B<sub>axial</sub> = (μ0/4π)(2m/r³) while the equatorial field is B<sub>equatorial</sub> = (μ0/4π)(m/r³), giving a ratio of 2:1.
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.