What does "the net electric field inside a conductor is zero" mean? does it mean that every point inside a conductor has a net electric field of zero, or am I missing something?
Because if we teleported a test charge inside a conductor, and the electric field is zero, won't it just stay where it is? I'm obviously missing something fundamental here.
does it mean that every point inside a conductor has a net electric field of zero
Yes. Note that this is only the case for a conductor in an electrostatic situation. When there is current there can be a non-zero electric field inside a conductor.
Because if we teleported a test charge inside a conductor, and the electric field is zero, won't it just stay where it is?
According to Maxwell’s equations it is not possible for a charge to teleport. Charge is conserved, so for charge to appear somewhere there must be a current.
However, what can suddenly appear is a charge dipole. If a dipole were to suddenly appear in a conductor then momentarily the conductor would not be electrostatic. The field would not necessarily be zero.
In response to the non-zero field, by Ohm’s law there would be a current. This current would flow so as to cancel out the dipole, returning the charge and the field back to zero as quickly as the conductor can conduct current.
This phenomenon is referred to as electrostatic shielding. $\vec E_{net}$ = $0$ when there are no charges placed inside the volume of the closed conductor irrespective of whether there is an external $\vec E$ surrounding the conductor.
Say there is an electric field $\vec E_1$ from left to right outside the conductor. The electrons on the surface of the conductor will then align themselves such that the surface closer to the direction of $\vec E$ will be relatively negatively charged and the surface further from the direction of $\vec E$ will be positively charged. This creates an equal and opposite $\vec E_2$ within the conductor, thus cancelling out the external field and making $\vec E_{net} = 0$ within the conductor. Hope this helps.
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