Transcript Faraday`s Law of Induction

During the 1820s Faraday sought to discover how to
make electricity from magnetism. He achieved success
with the device pictured above on 29 August 1831.
When he passed an electric current through one coil
he induced an electric current in the other coil, which
flowed for a very brief period of time.
When Michael Faraday made his
discovery of electromagnetic induction in
1831, he hypothesized that a changing
magnetic field is necessary to induce a
current in a nearby circuit. To test his
hypothesis he made a coil by wrapping a
paper cylinder with wire. He connected the
coil to a galvanometer, and then moved a
magnet back and forth inside the cylinder.
During the 1820s Faraday sought to discover how to
make electricity from magnetism. He achieved success
with the device pictured above on 29 August 1831. It's
made from everyday materials such as wire made for
bonnets, although the iron ring seems to have been
specially made.
Faraday’s magnetic induction experiment.
Ampere's law applied to an infinitely-long wire
predicts a magnetic field of strength B=m0I/(2pr) a
radial distance r from the wire. The field B is
tangential to a circle of radius r centered on the
wire.
We therefore have (B/I)=(m0/2p)(1/r). B/I is
proportional to 1/r, and when plotted versus 1/r will
yield a straight line with slope (m0/2p).
Consider the magnetic field around an infinitely long wire due to a current I flowing through the wire.
But B has the same value a distance a away from
the rod, hence
For the simple example, only one current linking the closed path C, therefore N = 1
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Faraday's Law of Induction
The line integral of the electric field around a closed loop is equal to the
negative of the rate of change of the magnetic flux through the area enclosed
by the loop. This line integral is equal to the generated voltage or emf in the
loop, so Faraday's law is the basis for electric generators. It also forms the
basis for inductors and transformers.
Application to voltage generation in a coil
Gauss' law, electricity Gauss' law, magnetism Faraday's law Ampere's law
Maxwell's Equations
Index
Maxwell's equations concepts HyperPhysics***** Electricity and Magnetism
R NaveGo Back
Ampere's Law
In the case of static electric field, the line integral of the
magnetic field around a closed loop is proportional to the
electric current flowing through the loop. This is useful for
the calculation of magnetic field for simple geometries.
Gauss' law, electricity Gauss' law, magnetism Faraday's law
Ampere's law
Apply to charge conservation
Maxwell's Equations
Figure 6: Current i charging a capacitor as an
illustration of Maxwell’s displacement current (see
text).