The Motor Effect

This lesson covers the motor effect — the force on a current-carrying conductor in a magnetic field — as required by the Edexcel GCSE Physics specification (1PH0), Topic 8: Magnetism and Electromagnetism. You need to understand Fleming's left-hand rule, the equation F = BIl (Higher tier), and how a DC motor works.

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What Is the Motor Effect?

When a current-carrying conductor (a wire with current flowing through it) is placed in a magnetic field, it experiences a force. This force can cause the conductor to move. This is called the motor effect.

Conditions for the Motor Effect

For the motor effect to occur, you need:

1. A current flowing through a conductor.
2. An external magnetic field (from a permanent magnet or another electromagnet).
3. The current must not be parallel to the magnetic field — the force is greatest when the current is perpendicular (at 90°) to the field.