Physics question - polarization of atoms by voltage differential?

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Deke609

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Not really an audio question, and probably better for a physics forum, but I figure one or both of Doc B and PJ may know the answer off the top of their heads.

As I understand things, when a voltage differential is created across the two leads of a capacitor the atoms in the dialectric become polarized with the electron "cloud" of the atom shifting towards the positive pole and the nucleus shifting towards the negative -- such that the dialectric atoms now have +ve and -ve poles.

My question: is the same true of any substance, whether electrically conductive or not, across which a voltage differential is created? I have in mind a sort of instantaneous reaction where all the atoms between anode and cathode become polarized.

I've done a bit of googling and only found discussion of the polarization of insulators and the holding of static charge. Nothing as best as I can decipher about, for example, whether applying a voltage difference across a piece of copper wire causes the polarization of the copper atoms.

Such polarization makes intuitive sense to me, unless the flow of charge (current) counterbalances the tendency towards polarization. But I don't see why flow of current and polarization couldn't be present at the same time.

Just in case someone knows. MTIA, Derek




Deke609

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Reply #1 on: November 23, 2020, 08:16:20 AM
I think I found the answer and it's "yes", with "polarizability" varying according to atomic structure.  My initial googling included the term "voltage" and didn't turn up much. But substituting "electric field" for "voltage" turns up a bunch of hits about electrical polarizability in general.  It didn;t occur to me that physics speaks in terms of field theory not the electronics language of "voltages".

cheers, Derek



Offline caffeinator

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Reply #2 on: November 24, 2020, 03:45:52 AM
Iirc, frequently the phrase "potential difference" is used. I attached one of many hits I got using this as search criteria.

https://courses.lumenlearning.com/austincc-physics2/chapter/19-1-electric-potential-energy-potential-difference/



Deke609

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Reply #3 on: November 24, 2020, 07:08:00 AM
Thanks Caffeinator.

I've since learned in the intervening day that the issue with which I'm interested -- atomic/molecular polarization -- is really an aspect of electromagnetic field theory - Faraday's stuff. Thankfully, Faraday was a pure experimentalist and essentially math-illiterate so I find him readable (no calculus!). Somewhat dreading trying to tackle Maxwell's mathematization of Faraday -- but I suspect I'll have to at some point if I am to make heads and tails of one of PJ's recent posts about testing grid chokes.  Thank heavens for MIT's "Open CourseWare"!

cheers, Derek