A washing machine has a metal casing. A fault occurs inside the washing machine and a live wire touches the metal casing.
Explain how the earth wire and the fuse in the plug work together to protect the user from receiving an electric shock.
The washing machine contains a transformer to power its internal electronic controls. The input voltage to the transformer is 230 V230\text{ V}230 V and the output voltage is 11.5 V11.5\text{ V}11.5 V. The input coil of this transformer has 400040004000 turns.
Calculate the number of turns on the output 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.