A straight conducting wire is moved through a magnetic field and a voltage is induced across its ends. Describe four ways in which the magnitude of the induced voltage could be increased.

Pearson Edexcel International GCSE Physics (4PH1) — 6.3 Electromagnetic induction · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

1. Increase the speed of the wire through the field.
2. Use a stronger magnetic field.
3. Increase the length of wire in the field, e.g. by coiling or adding turns.
4. Increase the rate of change of the magnetic field through the wire.

Examiner tips

Use the exact wording from the mark scheme (speed, stronger field, longer wire, rate of change).
Number points clearly to show you have covered all four.
Mention the underlying formula V=Blv or V=BlΔv if you can, but keep it brief.

Common mistakes

Confusing the direction of the induced voltage with its magnitude.
Forgetting to mention the wire length or the rate of change of the field.
Using vague terms like "more magnetic field" instead of "stronger magnetic field".

Mark scheme (4 marks)

Move the wire more quickly / increase the speed of movement of the wire
Use a stronger magnetic field
Increase the length of the wire inside the magnetic field (e.g. by coiling the wire / using more turns)
Increase the rate at which the magnetic field changes through the wire / conductor

Key terms in this question

induced voltage · magnetic field