This key facts covers Key Facts — Electromagnetic Induction within Electromagnetic Induction for GCSE Physics. Revise Electromagnetic Induction in Magnetism for GCSE Physics with 18 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 14 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📋 Key Facts — Electromagnetic Induction
- Induction requires a CHANGE in magnetic flux — static field = no induction
- Induced EMF increases with: faster movement, stronger magnet, more turns, larger coil area
- Direction of induced current reverses when: direction of motion reverses, or magnet orientation reverses
- Generators use slip rings (AC) or split-ring commutator (DC) to connect rotating coil
- AC generator output: sinusoidal EMF, maximum when coil is parallel to field
- Lenz's law: induced current opposes the change that caused it
- Conservation of energy: work must be done to drive a generator — electrical energy comes from mechanical input
- Transformers also use electromagnetic induction — AC in primary coil induces AC in secondary coil