Download Electromagnetism

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Electromagnetism
Electricity AND Magnetism!
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Electric Current and Magnetism

Wherever there is electricity, there is
magnetism

An electric current produces a
magnetic field

The relationship between electricity
and magnetism is called
electromagnetism
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Solenoids

The magnetic field produced by a current
has three distinct characteristics
 Field can be turned on and off
 Just turn the current off!
 Field direction can be reversed
 Just reverse the direction of the
current!
 Field strength can change
 Just change the strength of the current!
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A coil of wire with a current is called a
solenoid
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Electromagnets
 What
is an electromagnet?
 A solenoid with a ferromagnetic core
 A strong magnet that can be turned on and off
 Where
do we use electromagnets?
 Audiotapes, videotapes, computer hard drives,
credit cards, and doorbells
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Strength of an Electromagnet
 There
are four ways to change the strength of an
electromagnet
 Change the ferromagnetic core
 Stronger core = Stronger magnet
 Change number of coils
 More coils = Stronger magnet
 Change position of coils
 Closer coils = Stronger magnet
 Change current
 More voltage = Stronger magnet