Answer: Tesla.
- A Ampere
- B Volt
- C Tesla
- D Weber
Correct answer: C. Tesla
Explanation: Magnetic field strength is measured in Tesla (T). 1 T = 1 N/(A m).
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.