In electromagnetism books, such as Griffiths or the like, when they talk about the properties of conductors in case of electrostatics they say that the electric field inside a conductor is zero.
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$\begingroup$ Possible duplicate: physics.stackexchange.com/q/22773/2451 $\endgroup$– Qmechanic ♦Commented May 26, 2014 at 15:13
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3 Answers
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In an ideal conductor electrons are free to move. So when you apply an electric field to the conductor the electrons will feel a force $F=qE$ and start to move. This causes a charge separation which produces an electric field by itself. The net electric field is therefore a superposition of the external field and the field due to the charge separation. The electrons will continue to move until the net electric field inside the conductor is zero.
Note1: From this physical picture you can also infer that the charges will always accumulate on the surface of the conductor.
Note2: If you are wondering how the electrons know how to rearrange so that the net electric field is zero, just assume that the net electric field is non-zero. This causes a force $F=qE$ and the charge will separate along the electric field lines. This creates an electric field which is opposite to the external field that created the charge separation.
answered May 26, 2014 at 15:15
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Remarkably, the question, in its current form, is word for word the opening sentence of this question
In electromagnetism books, such as Griffiths or the like, when they talk about the properties of conductors in case of electrostatics they say that the electric field inside a conductor is zero.
and is thus a duplicate.
Regardless, the answer is actually more a simple matter of logic rather than physics.
(1) By definition, charge is free to move inside a conductor.
(2) By definition, charge is not moving for the electro static case.
(3) Free charge is accelerated by an electric field.
Thus, it follows that, in the electrostatic case, there is no electric field inside a conductor since, if there were, it would not be the electrostatic case as there would be acceleration of charge.
answered May 26, 2014 at 15:24
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As long as electric field is not zero, charge carriers (e.g., electrons) keep moving inside a conductor, so to say, steady state has not been reached. And in a steady state no charge carriers are moving and electric field must be zero.
