A transformer has 400 turns on its primary coil and 8000 turns on its secondary coil.
Connected in this way, for what purpose could this transformer be used?
to convert a 120 000 V a.c.120\,000\text{ V a.c.}120000 V a.c. grid voltage to 6000 V a.c.6000\text{ V a.c.}6000 V a.c. for a local substation
to use a 12 V d.c.12\text{ V d.c.}12 V d.c. battery to operate a 240 V240\text{ V}240 V refrigerator
to use a 12 V a.c.12\text{ V a.c.}12 V a.c. power supply to run a 240 V240\text{ V}240 V neon sign
to convert a 6000 V d.c.6000\text{ V d.c.}6000 V d.c. supply to 120 000 V d.c.120\,000\text{ V d.c.}120000 V d.c. for long-distance transmission
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.