Answer: the angle of deflection.
- A the square of the current
- B the magnetic field strength
- C the number of turns
- D the angle of deflection
Correct answer: D. the angle of deflection
Explanation: The spring provides a restoring torque proportional to the deflection angle. Balancing it against the magnetic torque NIAB gives deflection proportional to current.
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.