The primary voltage supplied to a transformer is 6.0 V. The secondary voltage is 15.0 V and the secondary current is 1.2 A. The transformer is 100% efficient.
What is the primary current in the transformer?
0.48 A0.48\text{ A}0.48 A
1.2 A1.2\text{ A}1.2 A
3.0 A3.0\text{ A}3.0 A
7.5 A7.5\text{ A}7.5 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.