Induced potential, transformers and the National Grid (physics only) (HT only)

EasyMediumHard
123
Question 3
Hard

An alternator with slip rings is used to generate alternating current. The diagram shows the inside parts of the alternator connected to a resistor in a complete circuit:

An alternator featuring a rectangular coil mounted on an axis of rotation between the curved north and south poles of a permanent magnet. The two ends of the coil are connected to two separate, continuous slip rings. Carbon brushes press against the slip rings, connecting them to an external circuit containing a resistor.

a.

The coil is rotated. Explain why an alternating current is induced in the circuit.

[4]
b.

Describe the shape of a graph showing how the potential difference generated across the resistor varies with time for two complete revolutions of the alternator coil.

[1]
c.

The resistor is disconnected from the alternator. Explain why the alternator's coil becomes much easier to turn.

[3]

Induced potential, transformers and the National Grid (physics only) (HT only) Questions

  1. GCSE
  2. /Physics
  3. /Induced potential, transformers and the National Grid (physics only) (HT only)