The electricity supplied to a region is transmitted using a high-voltage cable. A transformer in the local substation has a soft-iron core.
Explain the principle of operation of a simple electromagnetic iron-cored transformer.
The transformer steps the supply voltage down from 132 000 V132\,000\text{ V}132000 V to 11 000 V11\,000\text{ V}11000 V.
There are 350350350 turns on the secondary coil. Calculate the number of turns on the primary coil.
The transformer steps the supply voltage down from 132 000 V132\,000\text{ V}132000 V to 11 000 V11\,000\text{ V}11000 V.
The electrical power transferred to the transformer by the high-voltage cable is 66 MW66\text{ MW}66 MW. 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.