State what the split-ring commutator and the brushes do.
An upward force is shown on the left side of the coil. A magnetic field is present in the gap between the ends of the magnets. State the direction of this magnetic field. Explain how you worked out this direction.
State what happens to the coil’s rotation if both the magnetic field and the current in the coil are reversed at the same time.
In Fig. 7.1, the coil lies horizontally. The upward force on the left side and the downward force on the right side are both 2.3 N. The distance between the sides of the coil and the axis is 0.15 m. Calculate the total moment acting on the coil due to these forces. Give the unit of your answer.
Explain why the turning effect gets smaller as the coil becomes more vertical.