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Why is induced electric field circular?

  1. Dec 9, 2015 #1
    Time-varying magnetic field makes electric field circular(or close loop). I am asking the reason why it is circular or close loop shape?
  2. jcsd
  3. Dec 9, 2015 #2


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    The fields are non-conservative. They have to follow the laws of electromagnetism ( discovered by Faraday and Maxwell). In this case, electric field is induced only when there is change in magnetic flux associated with a loop (real or hypothetical).
    So,∫ E⋅dl=dΦB/dt.
    Since the varying flux is associated with a loop, the electric field lines are circular, i.e. they are along the loop. Everything is governed by Maxwell's mighty equations.
  4. Dec 9, 2015 #3


    Staff: Mentor

    Any vector field can be decomposed into an irrotational part and a solenoidal part. Faraday discovered that the solenoidal part is equal to the time variation of the magnetic field.
  5. Dec 9, 2015 #4
    Thank you. But I asked how time-variation of the magnetic field makes electric field rotate, not make it divergence field.
  6. Dec 9, 2015 #5


    Staff: Mentor

    Yes. That is what I answered. "Faraday discovered that the solenoidal part..."

    Faradays law says ##\nabla \times E =\partial B/\partial t##. In words this says that the circular part of E is equal to the change of B.
    Last edited: Dec 9, 2015
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