A transformer has 4000 turns on the primary coil and 200 turns on the secondary coil.
The output of the secondary coil is 12 V a.c. and is connected to a lamp. The transformer is 100% efficient.
The lamp produces a power of 60 W.
What is the current in the primary coil?
0.25 A0.25\text{ A}0.25 A
0.50 A0.50\text{ A}0.50 A
2.5 A2.5\text{ A}2.5 A
5.0 A5.0\text{ A}5.0 A
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.