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I Does a wire loops' magnetic field affect it's current?

  1. Apr 11, 2017 #1
    When you run current through a circle formed wire it generates a magnetic field. Will this field affect the current in the wire that generates it?

    I mean if it does wouldn't the calculations for the created magnetic field be rather circular?
    The magnetic field depends on the current which in turn depends on magnetic field which depends on current and so on..
  2. jcsd
  3. Apr 11, 2017 #2


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    Whilst the current is actually changing, there is a self induced emf in the circle. (read about Self Inductance) This is referred to as a 'back emf' because it acts against the current flow. (Lenz's Law) This effect decreases to zero eventually and the current reaches a steady value which is governed only by the DC resistance of the wire. An Inductor with very many turns of wire and an iron core will have such a high inductance that the current may take several seconds to establish itself. A small loop of wire may take only a few ns to settle down.
    Edit: PS Welcome - I only just noticed that you're new here.
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