A hand-operated exhibit turns a coil steadily between magnetic poles. The measured potential difference rises from zero to a positive maximum, returns to zero and repeats without becoming negative.
Which statement describes how the rotating coil is connected to the external circuit?
A split-ring commutator reverses the magnet's poles each time the potential difference reaches zero.
Two slip rings keep each coil end connected to the same brush throughout the rotation.
A split-ring commutator changes which brush contacts each coil end as the induced potential difference reverses.
Two slip rings disconnect both coil ends whenever the potential difference would become negative.
92 exam-style questions on Edexcel GCSE Physics 13.1 Inducing a current, covering 13.1.1 Producing an electric current by induction, 13.1.2 Factors affecting the induced potential difference, 13.1.3 Alternators and dynamos, and 13.1.4 Microphones and loudspeakers. Each one has a worked solution and a mark scheme showing where the marks go.