An electrical grid transmits power over long distances. To reduce power loss in the transmission cables, transformers are used.
Which row in the table correctly identifies how the voltage is changed at the power station prior to transmission, and the resulting effect on the current flowing through the transmission lines?
Voltage: decreases; current: increases
Voltage: decreases; current: decreases
Voltage: increases; current: increases
Voltage: increases; current: decreases
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.