An engineer designs four different transformers. The number of turns on the primary and secondary coils for each transformer, along with their labels, are shown in the table.
| Number of turns on the primary coil (NpN_\text{p}Np) | Number of turns on the secondary coil (NsN_\text{s}Ns) | Type of transformer | |
|---|---|---|---|
| A | 80 | 80 | step-down |
| B | 120 | 40 | step-up |
| C | 50 | 250 | step-up |
| D | 240 | 120 | step-up |
Which row shows the correct label?
A
B
C
D
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.