Magnetism and magnetic materials
4 marks · NormalThe table below shows four materials and their uses.
| Material | Use |
|---|---|
| Soft iron | Electromagnet core |
| Steel | Permanent magnet |
| Copper | Electric wiring |
| Plastic | Insulation |
Which materials in the table are magnetic? State their uses.
Explain why soft iron is used as the core of an electromagnet while steel is used for permanent magnets.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Soft iron (electromagnet core) and steel (permanent magnet) are magnetic. · must show Soft iron, Steel
(b) Soft iron is used because it is easily magnetised and demagnetised, suitable for turning the electromagnet on and off. Steel is hard to magnetise and demagnetise, so it is good for permanent magnets. · must show Soft iron: easily magnetised/demagnetised, Steel: remains magnetised
Common mistakes: Misidentifying copper as magnetic; Wrong justification for use
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies soft iron as magnetic and gives its use.
B2 (a) · 1 mark · Identifies steel as magnetic and gives its use.
B3 (b) · 1 mark · Explains why soft iron is suitable for the core of an electromagnet.
B4 (b) · 1 mark · Explains why steel is suitable for permanent magnets.
Worked solution
(a) Soft iron (electromagnet core) and steel (permanent magnet) are magnetic.
(b) Soft iron can be magnetised and demagnetised easily, perfect for switching electromagnets on and off. Steel is hard to magnetise and stays magnetised, so it is used for permanent magnets.