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ELECTROMAGNETIC INDUCTION Magnetism to electricity

ELECTROMAGNETIC INDUCTION Magnetism to electricity

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ELECTROMAGNETIC INDUCTIONMagnetism to

electricity

ELECTROMAGNETIC INDUCTION

The production of electricity by magnetism is called electromagnetic induction.

Faraday’s law of electromagnetic induction states: A changing magnetic field in the region of a

closed-loop conductor will induce an electric current.

EMF When a wire moves through a magnetic field

not only is a current induced, but an electric potential difference is also induced.

This induced electric potential difference is often called the electromotive force (emf).

An emf and current can only be induced in a wire if the wire moves perpendicular to the magnetic field

EMF

INDUCED CURRENT Faraday discovered that three factors influence the

magnitude of the emf and induced current in the wire.

These factors are:

1. velocity of the wire

as the velocity increases, the emf and induced current increase

2. strength of the magnetic field

as the strength of the magnetic field increases, the emf and induced current increase

3. length of the wire in the external magnetic field

As the length of the wire increases, the emf and induced current increase

Use pHet Simulation to demo

ELECTROMAGNETIC INDUCTION

WHY IS AN INDUCED CURRENT CREATED?

LENZ’S LAW Lenz’s law: An induced current and emf are in

such a direction as to oppose the change that produced them.

In other words, the induced current will create a magnetic force that acts on the wire. The direction of this force is opposite to the direction of the wire’s velocity.

LENZ’S LAW

LENZ’S LAW

LENZ’S LAWDetermine the direction of the induced current in the solenoid

LENZ’S LAWWill a current be induced in the wire segment shown in the following diagram? Explain your answer.