You are viewing a free preview of this lesson.
Subscribe to unlock all 10 lessons in this course and every other course on LearningBro.
The motor effect describes the force experienced by a current-carrying conductor placed in a magnetic field. This is one of the most important principles in the AQA GCSE Physics magnetism topic (specification 4.7.2) and underpins the operation of electric motors, loudspeakers and many other devices.
When a conductor (wire) carrying an electric current is placed in a magnetic field, the wire experiences a force. This is called the motor effect.
The force arises because the magnetic field around the current-carrying wire interacts with the external magnetic field. Where the two fields are in the same direction, the combined field is strengthened. Where they are in opposite directions, the combined field is weakened. This imbalance creates a net force on the wire.
Exam Tip: The motor effect only occurs when the current-carrying conductor is NOT parallel to the magnetic field. The force is greatest when the wire is at right angles (perpendicular) to the field lines, and zero when the wire is parallel to them.
For the motor effect to occur, three things must be present:
Subscribe to continue reading
Get full access to this lesson and all 10 lessons in this course.