Question
Compare the construction and output of an a.c. generator (alternator) and a d.c. generator (dynamo). (4 marks)
Mark scheme (4 marks):
- Both have a coil rotating in a magnetic field (or magnet rotating near a coil) (1)
- Alternator uses slip rings and brushes; dynamo uses a split-ring commutator (1)
- Alternator output reverses direction every half-turn → alternating current (1)
- Dynamo commutator reverses the connections every half-turn so output never changes sign → pulsed direct current (1)
Maximum 4. Award the comparison marks only if both devices are referenced.
4 marks · take your time before peeking.
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Generated by TopMyGrade AI · cross-check official sources before relying on the mark-scheme phrasing.