Electromagnetism - The Burns Home Page

03/12/2010
Electromagnetism Review
Magnetic Flux by Strengthening the Field
Electromagnetism Review
Magnetic Flux Practice Question
B BAcos
You have a hula loop of radius 0.5m that is immersed
in the Earth’s magnetic field (5x10 -5 T). The hula loop
is oriented in such a way that the normal is tilted at an
angle of 20 0 away from the Earth’s North pole. What is
the flux through the hoop?
B BAcos
B
B r 2 cos
You can increase the
magnetic Flux by
Strengthening the Field.
.5 20
B 5 10 T 0 m cos
5
3.710
Wb
B
5 2
Electromagnetism Review
Faraday’s Law
Electromagnetism Review
Faraday’s Law
Induction
Law of Induction
Faraday’s Law describes the
relationship between Electric Current
and Magnetism.
An Electric Current can induce a
Magnetic Field, and a Magnetic Field
can induce a Electric Current.
Induced Voltage, V.
A voltage is generated a Magnetic
Force has been traditionally called
an Electromotive Force or emf.
The number of coils
of wire
N
t
Change in Magnetic
Flux, Wb
Change in time, s
Just as Electricity needs to be moving
to create a Magnetic field B, The
Magnetic field B needs to be moving
to create an Electric Current .
•The greater the change in Magnetic Flux in a wire loop, the
greater the Induced Current.
•Less time corresponds to a greater Induced Current.
•Adding more loops corresponds to a greater Induced Current.
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