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AQA · GCSE · Combined Science · Higher

Force on a current-carrying wire

Q04.1 2 marks

A teacher demonstrated the motor effect. Figure 5 shows the equipment used.

Diagram of a current-carrying wire placed between two magnets labelled N and S, with the current direction shown along the wire.

Figure 5

Enlarged question image

Diagram of a current-carrying wire placed between two magnets labelled N and S, with the current direction shown along the wire.
Figure 5

Explain why there is a force on the wire when there is a current in the wire.

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Marking points

  1. 1 State that the permanent magnets produce a magnetic field.
  2. 2 State that the current in the wire produces a magnetic field.

Full-mark answer

The permanent magnets produce a magnetic field, and the current in the wire also produces a magnetic field. The interaction of these magnetic fields causes a force on the wire.

Why this answer loses marks

There is a force because electricity pushes the wire.

This does not identify the magnetic fields involved in the motor effect.

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