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Experiment to verify Faraday's Law
of Electro-Magnetic-Induction
| 1.
Preparation: |
a) |
Learn the
law. |
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b) |
Make sure you
understand why a signal generator with "floating" output must be
used (see part 4). |
| 2. |
The
method suggested here uses this basic circuit |
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An alternating current,
I of variable
frequency, flowing in one coil (the primary coil), induces an
alternating emf,
 ,
in the other coil (the secondary coil). In practice it is
convenient to use two coils wound on the same support.
We will need to find how the current in the primary coil
varies and how the induced emf in the secondary coil varies.
Both these quantities can be measured using a dual beam
oscilloscope.
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The resistor R
should be about 200W.
Why is this resistor needed?
Set the signal generator to "triangle" output, amplitude maximum,
frequency ×1kHz. Why do we choose this "shape" of signal?
Measure
for frequencies, f, in the range 500Hz to 5kHz. |
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Each time the frequency is changed, verify
that the peak voltage given by the signal generator remains the
same. |
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| 3. |
You will be expected to explain |
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why the signal generator is set
to "triangle" output and why you must maintain a
constant peak voltage |
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why resistor R is needed |
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- how
your results verify Faraday’s law (assuming that they do!) |
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Your report should also include a diagram
showing what you saw on the oscilloscope screen. |
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4. |
The experiment will be done using a coil like
the one shown below. In this case the primary and secondary
coils are two halves of the same coil. In other words,
the two coils are already connected together (as shown in the
circuit diagram). This means you must use a signal generator
which does not have one side of its output connected to
ground (the output must be "floating"). |
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© David Hoult 2009 |
The
Open Door Web Site