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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
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SilverSolder:

--- Quote from: rfeecs on January 21, 2022, 09:53:47 pm ---
--- Quote from: SilverSolder on January 21, 2022, 09:50:06 pm ---How would you draw the magnetic lines of force in this example?   I really am struggling to see it.  I'm probably overlooking something obvious.

--- End quote ---
It would be like a coaxial cable with a very thin dielectric.


--- End quote ---

So you are saying the thinner we make the insulator, the stronger the magnetic and electric fields will become (to carry the same amount of energy as before)?
HuronKing:
*Edit*
Others got to this before I could but posting for extra info in case it helps:


--- Quote from: SilverSolder on January 21, 2022, 09:39:14 pm ---The wires are very thin, 0.01mm, just enough to light a small bulb.  The insulation is the thinnest possible layer of vacuum that you can have without flashing over (a few micrometers), and the box is at least 500mm thick.

I am struggling to understand how the fields will be able to carry energy to the bulb.  And if they do make it in...  wouldn't the tortuous path they have to take to get there mean there would be more resistance, compared to a layout that does not impede the fields in any way?

--- End quote ---

You need to study waveguides. The penetrations cavities through the conductive enclosure with the conducting wire inside the penetration will follow the physics of waveguides... and in essence you've described a penetration that will have characteristics of a coaxial cable.

Long conducting outer shield, very thin internal dielectric, and an inner conductor. The energy is transmitted in the field in the dielectric between the conductors.
https://www.electricalengineeringtoolbox.com/2016/12/basics-of-coaxial-cables-used-in.html

Notice that the velocity of propagation depends chiefly on the insulation you use, the dielectrics:
https://en.wikipedia.org/wiki/Velocity_factor

And the amount of energy stored in these fields depends on the shaping of the conductors and the dielectrics:
https://phys.libretexts.org/Bookshelves/University_Physics/Book%3A_University_Physics_(OpenStax)/Book%3A_University_Physics_II_-_Thermodynamics_Electricity_and_Magnetism_(OpenStax)/14%3A_Inductance/14.04%3A_Energy_in_a_Magnetic_Field

This was Heaviside's great insight into Maxwell's Equations that led him to invent and patent coaxial cables in the first place (I think it was a mistake by Veritasium to show Heaviside's photo and talk about the Transatlantic Cable... and never mention coaxial cables, but I digress).

*Edit2*

Corrected a statement about the velocity propagation and its relationship to the conductivity. This should clarify what I mean:
https://phys.libretexts.org/Bookshelves/Electricity_and_Magnetism/Book%3A_Electromagnetics_II_(Ellingson)/03%3A_Wave_Propagation_in_General_Media/3.11%3A_Good_Conductors

And after all the math analyzing permittivity and conductivities, the key conclusion is:

--- Quote ---Thus, the information conveyed by signals propagating along transmission lines travels primarily within the space between the conductors, and not within the conductors. Information cannot travel primarily in the conductors, as this would then result in apparent phase velocity which is orders of magnitude less than  c , as noted previously. Remarkably, classical transmission line theory employing the  R′ ,  G′ ,  C′ ,  L′  equivalent circuit model2 gets this right, even though that approach does not explicitly consider the possibility of guided waves traveling between the conductors.
--- End quote ---
SilverSolder:

Let's take a step back, maybe I'm missing the point completely.

Are the fields that carry the energy outside the conductors normal electric and magnetic fields that we can measure if we want to?

bdunham7:

--- Quote from: SilverSolder on January 21, 2022, 10:35:54 pm ---
Let's take a step back, maybe I'm missing the point completely.

Are the fields that carry the energy outside the conductors normal electric and magnetic fields that we can measure if we want to?

--- End quote ---

Yes.  The 'S-field' vector at any point is the cross product of the E and H field vectors at that point.
SilverSolder:

--- Quote from: bdunham7 on January 21, 2022, 10:41:51 pm ---
--- Quote from: SilverSolder on January 21, 2022, 10:35:54 pm ---
Let's take a step back, maybe I'm missing the point completely.

Are the fields that carry the energy outside the conductors normal electric and magnetic fields that we can measure if we want to?

--- End quote ---

Yes.  The 'S-field' vector at any point is the cross product of the E and H field vectors at that point.

--- End quote ---

Ah, OK.  So we are really just playing around with cause and effect?   I.e. whether current is the result of the fields, or vice versa.   

The mathematics work out either way...    just like the math works great no matter which direction we believe the current is flowing between plus and minus.   The math can't be used to prove the direction one way or the other...
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