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Electromagnetic Induction (EMI) AP Physics
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Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Jan 03, 2016

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Page 1: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Electromagnetic Induction(EMI)

AP Physics

Page 2: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Electromagnetic Induction (EMI)A changing magnetic field can induce a current in a circuit

called the induced current.

The corresponding emf that must be present to cause the current is the induced emf.

Page 3: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

What Causes Induction

Page 4: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Magnetic Flux (φm)The amount of magnetic field there is in an area. (The number

of magnetic field lines in an area.)

Units of φm:

Only the components of

magnetic field that are perpendicular

to the area contribute to the

flux.

θ

Page 5: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Magnetic Flux (φm)

θθ

θ

Page 6: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Faraday’s LawBut wait…to have induction there must be a change in the magnetic field

(therefore a change in the magnetic flux)!!

“The induced emf in a circuit equals the rate of change of the magnetic flux through the circuit.”

Page 7: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Flux ProblemThe U-shaped conductor lies perpendicular to a uniform magnetic field B

with magnitude B = 0.60 T, directed into the page. We lay a metal rod with length L = 0.10 m across the two arms of the conductor, forming a conducting loop, and move the rod to the right with constant speed v = 2.5 m/s. What is the magnitude of the resulting emf?

Page 8: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

GeneratorsA device that converts mechanical energy to electrical energy.

Alternating current generator (alternator)

Page 9: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Lenz’s Law“The direction of any magnetically induced current or emf is such as to

oppose the direction of the phenomena causing it.”

Page 10: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Lenz’s LawLenz’s Law requires some thinking!

Page 11: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Motional emfThe induced emf in a circuit equals the rate of change of the

magnetic flux through the circuit.

Page 12: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

TransformersA device that converts voltage.

Page 13: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Power Transmission

Page 14: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Physics Rock BandElectromagnetic Induction is used to ROCK

OUT!!• Microphones

Page 15: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Physics Rock BandElectromagnetic Induction is used to

ROCK OUT!!• Electric Guitar

Page 16: Electromagnetic Induction (EMI) AP Physics. Electromagnetic Induction (EMI) A changing magnetic field can induce a current in a circuit called the induced.

Physics Rock BandElectromagnetic

Induction is used to ROCK OUT!!

• Cassette Tapes (kickin’ it old school)