A moving coil galvanometer uses a radial magnetic field so that
- A. the coil experiences a constant torque whatever its angular position
- B. the coil turns faster
- C. the current is increased
- D. the coil never moves
Explanation
With curved pole pieces and a soft iron core the field is always parallel to the plane of the coil, so the torque stays proportional to the current at every angle and the scale is linear. Without it the torque would fall off as the cosine of the deflection and the scale would be cramped at the ends. The restoring couple comes from a hair spring.
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