Faradays laws lenz law

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Faraday’s law, Lenz law

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Transcript of Faradays laws lenz law

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Faraday’s law, Lenz law

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FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION

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Faradays law of Electro Magnetic Induction

Basic Requirements1. Magnetic field2. Set of conductors (NOTE: They are just a set

of conductors not a current carrying conductors)

3. Relative space variation or4. Relative time variation

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Dynamically Induced emf

Magnetic field – steady/ time invariantSet of conductors – being moved

• This is the emf induced in set of conductors when they are being moved in steady magnetic field.

• The nature of emf induced in DC generator is dynamically induced emf.

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Statically Induced emf

Magnetic field –Time variantSet of conductors – stationary• This is the emf induced in set of stationary

conductors placed in time varying magnetic field.

• The nature of emf induced in transformer is statically induced emf.

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• Magnitude of statically induced emf can be obtained by Faradays 2nd law

• Direction of statically induced emf can be found by applying Lenz’s law.

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Faraday’s law of induction:

[1 loop]

[N loops]

Faraday’s Law of Induction

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Lenz’s Law

• The minus sign gives the direction of the induced emf:

• A current produced by an induced emf moves in a direction so that the magnetic field it produces tends to restore the changed field.

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Lenz’s LawElectromagnetic Induction

The magnetic is moving away from the coil so the magnetic field is decreasing, thus the current is in a direction to off-set the decrease.

The magnetic is moving toward the coil so the magnetic field is increasing, thus the current is in a direction to off-set the increase.

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Electromagnetic InductionFaraday’s Law

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Electromagnetic InductionFaraday’s Law

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