A step-up transformer is used to increase the voltage of electricity before it is transmitted along long-distance overhead power lines.
Which of the following best explains the primary reason for increasing the voltage for transmission?
Increasing the voltage decreases the current, which reduces the rate of thermal energy dissipation in the cables.
Increasing the voltage increases the current, which reduces the total resistance of the cables.
Increasing the voltage decreases the electrical resistance of the cables.
Increasing the voltage increases the speed of electrons, allowing electrical energy to travel faster across the network.
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.