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Veritasium "How Electricity Actually Works"

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SandyCox:

--- Quote from: EEVblog on May 11, 2022, 11:03:52 am ---
--- Quote from: dunkemhigh on May 11, 2022, 10:40:49 am ---I think that's missing an important thing. No doubt we are all mostly agreed that there is some fields stuff going on before the wires are connected, but what it's really about is after that, when there is a solid wired connection. Does the energy flow in the wire, on the wire (skin) or is the wire merely a guide and the energy actually flows still in the field? As I see it, and it's sometimes tricky to remember what the argument is about, it's that last option which is the crux of the video and this discussion.

--- End quote ---

For me the question is entirely about DC and energy inside vs outside the wire. Nothing to do with switches, transmission lines, capacitors, inductors, transformer theory, antenna theory etc etc.

--- End quote ---
Exactly!

I think that, under static conditions, all the energy is transferred by the electrons. They gain electrostatic potential energy as they move through the battery and loose electrostatic potential energy as they move through the lightbulb. The electron's electrostatic potential energy should not be confused with their kinetic energy.

snarkysparky:
"The math works out for both DC and AC, and the claim is the same, the energy flow is outside/on the surface of the wire, even at DC. The entiriety of classical electrodynamics physics in built upon this."


But if you substituted the wires for tubes of the same diameter with copper outer shell of infinitesimal thickness the light bulb would not stay lit.   Some inner copper is required beyond just a shell covering.

vad:

--- Quote from: EEVblog on May 02, 2022, 05:43:26 am ---Hontas Farmer is back still saying the Derek is both right and wrong acording to QFT/QED

--- End quote ---

QED (as all other QFTs) is a perturbation theory that extends Classical Electrodynamics to a quantum scale. QED is by no means a more fundamental theory than Classical Electrodynamics, and as being the extension, QED cannot contradict Classical Electrodynamics at macroscopic level. https://arxiv.org/pdf/1201.5536.pdf

Because QED is the perturbation theory, its approximate mathematical framework quickly falls apart when trying to describe classical systems (systems with billions of photons, electrons), as discussed in this paper: http://old.cft.edu.pl/~birula/publ/ClassLimit.pdf

In other words, QED has it own domain, and Classical Electrodynamics has its own domain. These domains do not overlap. Within their respective domains each theory has been validated experimentally to a very high degree.

In other words, to describe energy transfer in macroscopic systems proposed in Veritasium experiments, the only scientific tool Physics has is Classical Electrodynamics, and it is accurate at given scales.

vad:

--- Quote from: EEVblog on May 11, 2022, 11:03:52 am ---For me the question is entirely about DC and energy inside vs outside the wire. Nothing to do with switches, transmission lines, capacitors, inductors, transformer theory, antenna theory etc etc.

--- End quote ---
The only EM energy that flows into the wires is the energy that cause wire heating. The rest of the EM energy flows outside the wires.

Here is a paper, where authors compute energy flows around cylindrical wire: http://sharif.edu/~aborji/25733/files/Energy%20flow%20from%20a%20battery%20to%20other%20circuit%20elements.pdf

Naej:

--- Quote from: hamster_nz on May 11, 2022, 05:01:05 am ---
--- Quote from: Naej on May 10, 2022, 05:13:03 pm ---Ah and of course, you say that 'energy is in electron' is false, but with no experimental evidence; so it's your opinion, not a fact.

--- End quote ---

 I charge two capacitors in series, to 10V (so 5V in each). While the power is still on I remove them, and put them on the bench.

They still have charge in them.

How can you tell which one was connected to 10V, and which was connected to 0V

--- End quote ---
Here is a funny exercise (not related to anything I said):
I charge 100 capacitors in series, to 1 MV.
While the power is still on I remove them, and put them on the bench.

They still have charge in them.

How can you tell which one was connected to 1MV, and which was connected to 0V?

If you're trying to say "all electrons are identical" then I agree.

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