Answer: mB sinθ.
- A mB sinθ
- B mB cosθ
- C always mB
- D m divided by B
Correct answer: A. mB sinθ
Explanation: τ = m × B = mB sinθ, where θ is the angle between the dipole and the field.
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.