The output of an a.c. generator in a power station is 8000 V. A step-up transformer increases the voltage to 120000 V before the electrical power is transmitted along transmission lines to a distant city.
State and explain, using a relevant equation, one advantage of transmitting electrical power at a high voltage.
The transformer contains two coils, the primary coil and the secondary coil.
State the other main component of a transformer and the material from which it is made.
State the component in the transformer to which the a.c. generator is connected.
There are 300 turns on the primary coil of the transformer. Calculate the number of turns on the secondary coil.
Step-down transformers near the city reduce the voltage to 240 V. Suggest one reason why this reduction in voltage is necessary.
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.