GCSE Physics · Edexcel 1PH0 · Topic 13A
Generators and induced potential difference
Key points
- Moving a wire across a magnetic field, or changing the field in a coil, induces a potential difference (electromagnetic induction).
- A bigger induced pd comes from moving faster, using a stronger magnet or using more turns of wire.
- Reversing the motion or swapping the poles reverses the induced pd.
- An induced current produces its own magnetic field that opposes the change causing it.
- An alternator (a.c. generator) uses slip rings; the output pd alternates as the coil rotates. A dynamo uses a split-ring commutator to give d.c.
- A microphone: sound waves move a diaphragm and coil in a magnetic field, inducing a varying pd that matches the sound.
Topic notesPremium
Moving a wire through a magnetic field, or changing the field through a coil, produces a potential difference. This is electromagnetic induction, and it is how power stations, bicycle dynamos and microphones generate electrical signals.
Unlock the full notes with Premium
Premium includes full topic notes, the paper generator, self-quizzes and progress tracking.
Practise this topicPremium
Premium members can generate an exam-style paper with a mark scheme, or take a quick quiz, on Generators and induced potential difference.