In summary, the presence of a changing magnetic field around each individual loop of wire in a coil carrying alternating current results in a back emf being induced. This is due to the changing flux through each loop caused by the changing field around all other loops. Even a single loop of wire is affected by its own magnetic field, which is measured by the inductance and can result in a reactance.
  • #1
21joanna12
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I have been thinking about coils of wire carrying alternatingcurrent. From what I understand, a back emf is induced in the coil because there is a changing magnetic field around each individual loop of wire, and therefore there is a changing flux through each loop because the changing field around all of the other loops passes through this loop. But what about a single loop of wire? Surely a back emf would not be induced, because this would require the loop to be affected by its own generated magnetic field... Or is this in fact the case?

Thank you in advance!
 
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  • #2
Yes, the loop is affected by its own magnetic field. This effect is measured by the inductance of the loop and result in a "reactance" of the loop, a quantity with the same units as resistance.
http://en.wikipedia.org/wiki/Electrical_reactance
 

What is back emf in a single loop of wire?

Back emf, or back electromotive force, is the voltage induced in a single loop of wire when there is a change in the magnetic field passing through the loop.

What causes back emf in a single loop of wire?

Back emf is caused by Faraday's law of induction, which states that a changing magnetic field will induce a voltage in a conductor.

How does back emf affect the performance of a single loop of wire?

Back emf can oppose the flow of current in a single loop of wire, causing a decrease in current and a decrease in the strength of the magnetic field created by the current.

How is back emf measured in a single loop of wire?

Back emf can be measured using a voltmeter connected across the loop of wire. The voltage measured will be equal to the back emf.

How can back emf be reduced in a single loop of wire?

Back emf can be reduced by using a material with lower electrical resistance for the wire, increasing the number of turns in the loop, or decreasing the speed at which the magnetic field changes.

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