Answer: zero.
- A 2.0 N/m
- B zero
- C 0.4 N/m
- D 1.0 N/m
Correct answer: B. zero
Explanation: The force on a current-carrying wire is F = BIL sinθ. When the wire lies along the field, θ = 0 and the force is zero.
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.