BRAINCAKEForce on a current-carrying wire
A wire carrying a current experiences a force in an external magnetic field. This is because the magnetic field around the wire due to the current interacts with the external magnetic field. This is known as the motor effect. The magnitude of the force is proportional to the size of the current I, the strength of the magnetic field B (magnetic flux density) and the length of the wire in the magnetic field l. The direction of the force can be found using Fleming's left hand rule and is at right angles to both the magnetic field and the current.
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Key terms in this lesson
- magnetic field
- A region of space in which a moving charge, current-carrying conductor or magnetic material experiences a force.
- magnetic flux density
- The strength of a magnetic field, equal to the force per unit current per unit length on a wire carrying current at right angles to the field.
- magnetic flux
- The product of the magnetic flux density and the area through which the field lines pass at right angles.
More in Magnetic Fields
- Magnetic Field
- Magnetic Flux density
- Couple on a coil in a magnetic field
- An Electric Motor
- Force on a moving Charge in a Magnetic Field
- Cyclotron
- The Mass Spectrometer
All 8 lessons in Magnetic Fields · All OCR A-level Physics topics