A simple d.c. electric motor has a coil that rotates inside a magnetic field. A commutator links the power supply to the coil. What is the function of the commutator?
- AIt converts a.c. into d.c. in the coil.
- BIt prevents the current from becoming too great, because the coil has a low resistance.
- CIt reverses the direction of the current in the coil after every $180^$ rotation of the coil.
- DIt switches the current off momentarily after every $90^$ rotation of the coil.