In a simple d.c. generator, a coil is rotated at a constant rate in a uniform magnetic field. A split-ring commutator connects the rotating coil to the external circuit. What is the function of this split-ring commutator?
to reverse the direction of the induced e.m.f. inside the coil every half revolution
to convert the alternating e.m.f. induced in the coil into a unidirectional e.m.f. across the external circuit
to ensure the current inside the rotating coil always flows in a single, constant direction
to prevent any induced e.m.f. when the plane of the coil is perpendicular to the magnetic field
35 exam-style questions on CIE IGCSE Physics 4.5.1a Electromagnetic induction. Each one has a worked solution and a mark scheme showing where the marks go.