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Veritasium "How Electricity Actually Works"

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electrodacus:

--- Quote from: HuronKing on May 18, 2022, 11:48:18 pm ---I've been reading this discussion and I'm intrigued that pages and pages have gone by and the two words - "displacement current" haven't been mentioned (if they have I missed it!).

If one thinks currents only exist where charge flows, then one would be taking issue with Maxwells Eqs:
https://en.wikipedia.org/wiki/Displacement_current

--- End quote ---

You will need to understand Maxwell's equations to understand what they say. They do not say energy flows outside the wires.
Electrons accumulate in to the wires (capacitor plates) and energy is stored that way. The higher the capacitance the more electrons you can push on to plates (conductors/wires).
If you disconnect the battery the potential difference will stay there as stored energy and if you short the two plates electrons will flow through wires from one plate to another discharging the capacitor while energy will end up as heat in the wire as that is the space energy traveled through the wire and not the air space between the plates.

hamster_nz:

--- Quote from: electrodacus on May 18, 2022, 11:04:31 pm ---Electrons flow in to wire but do not jump that gap and since electron flow is electrical current and electrical current multiplied with voltage is power and power integrated over time is energy it means energy flows only in wire.

--- End quote ---

By your own logic, if a wire has 1A flowing it, but almost zero voltage drop across the wire, then integrating the power over time for that wire proves that there is minimal energy in that wire.

If you do the same calculation for the resistor you get reliable results, so why not for a wire? What is so special about it?

And where along the transition between "resistor" and "wire" does this specialness happen? at what resistance or current does your own math become invalid?

electrodacus:

--- Quote from: hamster_nz on May 18, 2022, 11:59:29 pm ---
By your own logic, if a wire has 1A flowing it, but almost zero voltage drop across the wire, then integrating the power over time for that wire proves that there is minimal energy in that wire.

If you do the same calculation for the resistor you get reliable results, so why not for a wire? What is so special about it?

And where along the transition between "resistor" and "wire" does this specialness happen? at what resistance or current does your math become invalid?

--- End quote ---

A wire is a resistor with lower resistance so there is no difference.
Not quite sure you know what you are asking. Can you be more exact maybe give a proper example with values.

Yes 1A drop on a 0.1Ohm resistor will result in a 0.1V drop across the resistor/wire and thus 0.1W of power lost on the wire as heat.
Same 1A on a 1kOhm wire/resistor will result in 1000V drop thus 1000W of power loss on that wire/resistor.

Where do you see any difference or problem between the two examples ?
 

hamster_nz:

--- Quote from: electrodacus on May 19, 2022, 12:03:30 am ---
--- Quote from: hamster_nz on May 18, 2022, 11:59:29 pm ---
By your own logic, if a wire has 1A flowing it, but almost zero voltage drop across the wire, then integrating the power over time for that wire proves that there is minimal energy in that wire.

If you do the same calculation for the resistor you get reliable results, so why not for a wire? What is so special about it?

And where along the transition between "resistor" and "wire" does this specialness happen? at what resistance or current does your math become invalid?

--- End quote ---

A wire is a resistor with lower resistance so there is no difference.
Not quite sure you know what you are asking. Can you be more exact maybe give a proper example with values.

Yes 1A drop on a 0.1Ohm resistor will result in a 0.1V drop across the resistor/wire and thus 0.1W of power lost on the wire as heat.
Same 1A on a 1kOhm wire/resistor will result in 1000V drop thus 1000W of power loss on that wire/resistor.

Where do you see any difference or problem between the two examples ?

--- End quote ---

None, as you say

--- Quote ---electrical current multiplied with voltage is power

--- End quote ---
Sure, a good wire has 1A flowing in it, and 0V measured across either end, so has 0W


--- Quote --- and power integrated over time is energy

--- End quote ---
Sure, let's integrate 0W for as long as we want.... it's 0 J.


--- Quote ---it means energy flows only in wire.

--- End quote ---
This doesn't follow - the result of your calculation is 0 J.

Well, following your own calculations, there was 0J in that wire.

If it was a 1 ohm resistor with 1A

"electrical current multiplied with voltage is power" - 1A at 1V is 1 W

" and power integrated over time is energy" - let's integrate 1W for a second.... it's 1 J.

Yep, 1J as expected. That checks out.

electrodacus:

--- Quote from: hamster_nz on May 19, 2022, 12:18:03 am ---
Sure, a good wire has 1A flowing in it, and 0V measured across either end, so has 0W
Sure, let's integrate 0W for as long as we want.... it's 0 J.


--- End quote ---

:) good wire ? You mean superconductor.
Yes you can have 1A induced in a superconductor ring and have that 1A flowing forever in there with no energy loss.

A good wire that is not a superconductor will have a resistance low enough that loss is not to high at 1A so that wire will not melt and it is acceptable in your application.
So a resistor is a wire and vice versa thus absolutely no difference between the two.

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