The coil inside a d.c. motor is attached to a split-ring commutator. What is the function of the split-ring commutator?
- Ato ensure that the coil continues to rotate in the same direction
- Bto ensure that the size of the current in the coil remains constant
- Cto ensure that the size of the turning effect on the coil remains constant
- Dto ensure that the turning effect on the coil changes direction