During long-distance electrical energy transmission, step-up transformers are used to increase the voltage. Which statement correctly explains why transmitting electrical energy at a high voltage is more efficient?
The resistance of the transmission cables decreases as the voltage increases.
For the same transmitted electrical power, a higher voltage leads to a smaller current in the cables, reducing the energy lost as thermal energy.
A higher voltage results in a larger current in the transmission lines, which speeds up the energy transfer.
High voltage allows the electrical energy to be transmitted as direct current instead of alternating current.
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.