Which row in the table correctly states the ideal materials for the coils and the core of a transformer, along with the physical reason for their choice?
| Material for Coils | Reason | Material for Core | Reason | |
|---|---|---|---|---|
| A | Copper | Low electrical resistance | Soft iron | Easily magnetized and demagnetized |
| B | Steel | High mechanical strength | Soft iron | Hard magnetic properties |
| C | Copper | Low electrical resistance | Plastic | Good electrical insulator |
| D | Iron | High magnetic permeability | Copper | High thermal conductivity |
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.