Can anyone draw the Field Lines of Faraday induced electric field

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Discussion Overview

The discussion revolves around the induced electric field lines resulting from the sudden removal of a uniform magnetic field oriented along the z-direction. Participants explore the characteristics of the electric field generated, including its behavior and representation without the context of a loop of wire.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes the scenario of a uniform magnetic field along the z-direction being turned off, prompting a question about the nature of the induced electric field lines and their curl.
  • Another participant provides a mathematical representation of the electric field and magnetic field using scalar and vector potentials, suggesting a relationship between them.
  • A request is made for a visual representation of the electric field lines when the magnetic field is suddenly turned off.
  • One participant asserts that the problem does not have a definitive answer, as the induced electric field can vary based on different parameters, producing multiple possible outcomes.
  • Another participant agrees that the choice of scalar potential is arbitrary, indicating that other potentials could also yield valid solutions.
  • A question is raised about the influence of boundary conditions, specifically regarding the scenario of the magnetic field being generated from a long solenoid and whether the electric field would curl around its axis.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the induced electric field and its representation. There is no consensus on a definitive answer to the problem, as multiple interpretations and models are presented.

Contextual Notes

The discussion highlights the dependence on boundary conditions and the arbitrary nature of the scalar potential chosen. There are unresolved aspects regarding the specific characteristics of the induced electric field lines.

AbhiFromXtraZ
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Suppose there is an uniform magnetic field along z-direction. Now someone turns off the field. Then there will be an induced electric field.
Can anybody draw this induced electric field lines?
I know the electric field will curl around. But where will be the centre of that curl.
Do the electric field lines curl around the individual magnetic field lines or anything elese.
If I consider a loop of wire then I can easily answer using Flux Rule or Lenz's law.
But I want the field lines without considering any loop.
Thanks.
 
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For a scalar potential ##\phi=0## and a vector potential ##A=(-y~f(t),x~f(t),0)## we have:
##B=\nabla \times A = (0,0,2f)##
and
##E=-\nabla \phi-\partial A/\partial t = (y~df/dt, -x~df/dt,0)##
 
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Can you show me the picture of the electric field lines if the magnetic field was constant and along z-direction and suddenly turned off?
 
You can get the picture from the equations I posted. Use a graphing software or even do it by hand. It should only take a couple of minutes.
 
ok...I have to figure it out...Thanks !
 
This problem doesn't have an answer. An electric field:

E_x = (y-y_0) \frac {dB_z}{dt}
E_y = -(x-x_0) \frac {dB_z}{dt}
E_z = 0

will work for every x0 and y0, and this can produce any magnitude and any direction (in the xy plane) for E.
 
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Yes. I chose ##\phi=0## for convenience, but any ##\phi## would also be a solution.
 
willem2, I think you are missing appropriate boundary conditions. Am I right? Well, if the magnetic field was generated from a long solenoid of radius 'r' , then would the electric field curl around the axis of the solenoid?
 

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