Answer: 1 N A -1 m -1.
- A 1 N A<sup>-1</sup> m<sup>-1</sup>
- B 1 N A m
- C 1 N C<sup>-1</sup>
- D 1 J C<sup>-1</sup>
Correct answer: A. 1 N A<sup>-1</sup> m<sup>-1</sup>
Explanation: From F = BIL, B = F/(IL), so the unit is newton per (ampere × metre) = N A<sup>-1</sup> m<sup>-1</sup>, which is the tesla.
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.