Is the Electric Field Always Conservative?

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Discussion Overview

The discussion revolves around the question of whether the electric field is always conservative, exploring the conditions under which this property holds. Participants examine theoretical aspects, definitions, and experimental methods related to conservative fields.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Experimental/applied

Main Points Raised

  • One participant seeks clarification on how to prove that the electric field is conservative, referencing line integrals.
  • Another participant explains that a conservative vector field has specific properties, including that the line integral is path-independent and the curl is zero, suggesting that the electric field can be expressed as the gradient of a scalar potential.
  • A different viewpoint is introduced, stating that only electrostatic fields are conservative, while electric fields induced by changing magnetic fields are not.
  • A further suggestion is made about an experimental approach to demonstrate whether an electric field is conservative by using a closed contour of wire and an ammeter to check for current flow.

Areas of Agreement / Disagreement

Participants express differing views on the conditions under which the electric field is conservative, indicating that there is no consensus on the matter. Some agree on the theoretical properties of conservative fields, while others challenge the universality of these properties in the context of changing magnetic fields.

Contextual Notes

The discussion highlights the distinction between electrostatic fields and those induced by time-varying magnetic fields, suggesting that assumptions about the nature of the electric field may affect conclusions about its conservativeness.

Identity
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How can you prove that the electric field is conservative? I've learned about stuff like line integrals but I'm not sure how to prove this particular fact.

Thanks
 
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A conservative vector field has the property that the line integral of the vector field is independent of the path and depends only on the end points. This implies that the line integral of the vector field around a closed path is equal to zero. An equivalent property is that the curl of a conservative vector field is equal to zero. Also, the curl of the gradient of a scalar function is equal to zero. The electric field can be expressed as te gradient of a scalar electric potential.

There are enough different ways hinted at in the above paragraph that I'm sure you can easily prove that the electric field is conservative.
 
Just want to point out that only an electrostatic field is conservative. The electric field induced by a changing magnetic field isn't.
 
Identity said:
How can you prove that the electric field is conservative? I've learned about stuff like line integrals but I'm not sure how to prove this particular fact.

Thanks

If you want to prove experimentally that some electric field is conservative, you can place a closed contour of electric wire, with an in-line ammeter, in the field. If no current flows regardless of the orientation of the wire, then you are dealing with a conservative field. If current does flow, then for selected orientations there is a non-zero emf around the contour and the field is not conservative.
 

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