# Does there exits an electric field in a wire not connected to battery?

I understand that if there exists a charged particle, then there is an electric field.

In a wire (or a conductor), there are electrons (a billions of them) which are seperated from protons (i.e. there is a non-null distance between the charged particles). Supposed that the wire is not connected to any source/battery. Does there exists any electric field in the wire?

Moreover, i understand that it is the electric field that causes the electric current, then in this case, if there exists electric fields, then why there isn't any electric current? Maybe because there is no loop? Then the question is why should the loop exist to have the current?

I think that i'm wrong somewhere but just can make up my mind.

• Why is the post downvoted ?? Commented Mar 10 at 6:35
• Ignore the downvotes. This seems a perfectly good question to me and The Photon's answer is fine. I have upvoted both your question and the answer. Commented Mar 10 at 7:18

Does there exists any electric field in the wire ?

Yes, viewed on a microscopic scale there exist tiny, and randomly oriented electric fields produced by the electrons. And relatively regular electric fields produced by the fixed protons.

(But be careful of taking this too literally as at quantum level the free electrons in a metallic conductor aren't normally found in states with well-defined positions)

if there exists electric fields, then why there isn't any electric current ?

The electrons (again, speaking in terms of a particle model, not consistent with QM) do move around randomly, in a manner resembling Brownian motion. So at microscopic scale, there are tiny currents. These are responsible for important noise effects in high-sensitivity electronics.

But at macroscopic scale there is no net current, because the direction of the electrons' motion is random, averaging out to zero motion when you sum up the effect from all the electrons together, and average over any appreciable period of time.

Then the question is why should the loop exist to have the current ?

A loop is required even when there is a battery or other voltage source, because it gives the electrons a place to go without piling up and producing their own electric field that would balance out the applied field.

• Hi, thanks for your help! I have just watched the video of Derek (youtu.be/oI_X2cMHNe0?feature=shared), at 13:20, he claims that the lightbulb still lit up even when the circuit is broken, so I think that the "loop" is not a necessary condition for the existence of the electric current. What do you think about it please ? Commented Mar 9 at 21:38
• @InTheSearchForKnowledge, 1. The circuit in the video is not a lumped circuit, so you can't use lumped circuit analysis on it without some special considerations. 2. There is a closed loop if you consider the capacitance between the "outgoing" wire and the "return" wire. Commented Mar 10 at 5:04