Physics · Oct / Nov 2023 · Paper 11 · Question 33

A commutator is connected to the coil of a d.c. motor. The commutator rotates and connects the coil to the power supply. Once every half-turn, the current in the coil reverses. [diagrams: coil perpendicular to magnetic field; coil parallel to magnetic field] What is the name of the commutator and what is the orientation of the plane of the coil as the current reverses?

1. Aslip ring; parallel to the magnetic field
2. Bslip ring; perpendicular to the magnetic field
3. Csplit ring; parallel to the magnetic field
4. Dsplit ring; perpendicular to the magnetic field

As printed in the paper