Question

What factors limit the size of the back e.m.f.?

Answer 1

Answer:

The back EMF depends, of course, on the speed of the motor — the change in magnetic flux that generates it increases with motor speed — so that as the motor begins to turn, the back EMF grows until the motor has reached its maximum speed, at which point the back EMF stays at its maximum value

Answer 2

Answer:

amount of current flowing and resistance of the circuit is the answer to the question