Answer: 1.5.
- A 0.5
- B 0.75
- C 1.5
- D 2.5
Correct answer: C. 1.5
Explanation: μ_r = 1 + χ = 1 + 0.5 = 1.5.
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.