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Homework Help: Electromagnet within a coil

  1. Apr 23, 2010 #1


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    Gold Member

    1. The problem statement, all variables and given/known data

    Hooking up voltage to a solenoid (coil of wire) creates an electromagnet. Moving the electromagnet in and out of a larger coil hooked up to a galvanometer creates an emf (voltage) in the larger current.

    Does an emf get created for a *stationary* electromagnet inside a larger coil of wire?

    2. Relevant equations

    Voltage generated = [tex]-N\frac{\Delta(BA)}{\Delta(t)}[/tex]

    3. The attempt at a solution

    My attempt at the solution included burning 3 resistors. I hooked up 6VDC to a 10 ohm resistor in series with the smaller coil (electromagnet). Before I could count to five, the resistor was glowing hot. I increased the resistor to 27 ohms and the same thing happened (twice).

    So, afraid of getting kicked by my professor, I wasn't able to directly see what was happening with a stationary electromagnetic coil inside the larger solenoid. Should the galvanometer's needle move when the electromagnet is stationary and not moving?
  2. jcsd
  3. Apr 23, 2010 #2
    Could you predict what will happen with the equation you wrote down?
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