Answer: 0.5 N·m.
- A 0.05 N·m
- B 0.5 N·m
- C 1 N·m
- D 5 N·m
Correct answer: B. 0.5 N·m
Explanation: τ = NIAB = 100·1·0.01·0.5 = 0.5 N·m (maximum, since plane is parallel to field).
The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).
Concept context
Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.