BRAINCAKELenz's Law
The direction of the induced current is always such as to oppose the change that causes a current.
When the north pole of a bar magnet is pushed into a coil, the induced current makes the end of the coil nearest the magnet a north pole. This repels the incoming magnet, so work must be done to push it in. When the magnet is pulled out, the current reverses and that end becomes a south pole, which attracts the magnet and opposes its removal. A meter connected to the coil deflects in opposite directions in the two cases.
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Key terms in this lesson
- faraday's law
- The induced e.m.f. in a circuit is equal to the rate of change of magnetic flux linkage through the circuit.
More in Electromagnetic Induction
- Electromagnetic Induction
- Energy Transfer
- A Dynamo
- Solenoid
- Faraday's Law of Electromagnetic Induction
- The Alternating Current Generator
- Power Station Alternators
- Back e.m.f.
All 12 lessons in Electromagnetic Induction · All Edexcel A-level Physics topics