A step-down transformer is used at a local substation to reduce the high transmission voltage to a lower voltage suitable for a residential area.
Explain how the transformer produces this lower output voltage.
Electricity is distributed to homes via overhead cables.
Explain why the power lost as heat in these cables increases significantly when the current flowing through them is increased.
Explain one advantage and one disadvantage of replacing standard transmission cables with cables of a larger cross-sectional area.
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.