Before electricity is transmitted over long-distance overhead power lines, a step-up transformer is used at the power station.
Which statement correctly explains the effects of this step-up transformer on voltage and current, and its main benefit?
It decreases the voltage and increases the current, preventing the cables from melting.
It increases the voltage and decreases the current, reducing the thermal energy lost in the cables.
It increases the voltage and increases the current, increasing the total power delivered.
It decreases the voltage and decreases the current, making long-distance transmission safer.
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.