Students are required to propose factors that influence the rotational speed of a direct current (d.c.) motor. Three suggestions are given below. 1 the strength of the magnetic field 2 the current 3 the number of turns on the coil Which of these suggestions are correct?
- A1, 2 and 3
- B1 and 2 only
- C1 and 3 only
- D2 and 3 only