A transformer is used to convert 240 V240\text{ V}240 V a.c. to 12 V12\text{ V}12 V a.c. The primary coil has 500500500 turns.
Calculate the number of turns on the secondary coil.
Describe how an alternating current in the primary coil of a transformer induces an alternating voltage in the secondary coil.
State one mechanism by which energy is lost as heat in a transformer and identify the part of the transformer where this loss occurs.
An adapter is labelled:
State the electrical output of this adapter.
Name the electrical component that must be included in the adapter, in addition to a transformer, to produce this output.
A step-down substation transformer converts the transmission line voltage of 33 000 V33\,000\text{ V}33000 V a.c. to a distribution voltage of 11 000 V11\,000\text{ V}11000 V a.c. The current in the secondary coil is 15 A15\text{ A}15 A.
Assuming 100%100\%100% electrical efficiency, calculate the current in the primary coil.
275 exam-style questions on CIE IGCSE Physics 4.5 Electromagnetic effects, covering 4.5.1a Electromagnetic induction, 4.5.1b Direction of an induced e.m.f., 4.5.2 The a.c. generator, 4.5.3a Magnetic effect of a current and its applications, 4.5.3b Strength and direction of the field around wires and solenoids, 4.5.4a Force on a current-carrying conductor, 4.5.4b Force on beams of charged particles, 4.5.5 The d.c. motor, 4.5.6a Construction and operation of a transformer, 4.5.6b Turns ratio and current in a transformer, and 4.5.6c High-voltage transmission of electricity. Each one has a worked solution and a mark scheme showing where the marks go.