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Physics 212Lenz's Law

Lenz’s Law

Examples Using Lenz’s Law

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Physics 212Lenz's Law

Lenz’s Law

The induced EMF and induced current are in such a direction as to oppose the change that produces them.

1.If the external magnetic flux increases, the magnetic field generated by the induced current is opposite in direction.

2.If an external magnetic flux decreases, the magnetic field generated by the induced current is in the same direction.

3.If there is no change in the external magnetic flux, there is no induced current.

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Physics 212Lenz's Law

Here is an example of the application of Lenz’s Law with an increasing external magnetic field

The induced EMF and induced current are in such a direction as to oppose the change that produces them.

externalB

I

inducedB

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Physics 212Lenz's Law

Here is an example of the application of Lenz’s Law with a decreasing external magnetic field

The induced EMF and induced current are in such a direction as to oppose the change that produces them.

externalB

I

inducedB

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Physics 212Lenz's Law

Motional EMF

The increase in area increase the flux, the induced magnetic field acts to oppose this increase.

I

externalB

inducedB

externalF

inducedF

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Physics 212Lenz's Law

Lenz’s Law

Examples Using Lenz’s Law