Answer: Uniform radial magnetic field.
- A Stationary magnetic field
- B Rotating magnetic field
- C Uniform radial magnetic field
- D No magnetic field
Correct answer: C. Uniform radial magnetic field
Explanation: A moving coil galvanometer uses a uniform radial magnetic field so that the torque is directly proportional to current at all deflections.
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.