Magnetic vs Electrical Propagation Speed

No.

The propagation rate of the two metals is not the same.

You have a serious misunderstanding of electromagnetic fields. You are measuring different manifestations of the same phenomena. The speeds will be virtually identical. The difference will come from the effects of differing geometries and media of the two configurations.

So, that's a no, yes?

It's hard to measure a speed of 186,282 miles per second with a stop watch.

It's difficult to measure that sort of speed with practically anything, really.

I realize that a magnetic field always accompanies an electric current,except in a superconductor.

However, a permanent magnet has no electrical field associated with it.

I also realize how a voltage can be induced by a magnetic field into a conductor.

So let me rephrase the question:

Apply a permanent magnet to the end of a steel wire.Presume the wire is 300,000 meters long.

At the exact same time, apply a voltage to a copper wire, with the exact physical dimensions and length.

Will the magnetic field arrive at end of the steel wire at the same time as the electrons,(and the induced magnetic field) arrive at the end of the copper wire?

When you move the magnet toward the wire, you will induce an electrical current.

Just accept it.

Do electrons move at the same speed through steel as through copper?

Now, you've confused the issue.

Electrons do not move at the approximate speed of light, but slower.

Are we talking about electrons or electricity?

Ok,let me clear that up.I realize that the actual electrons in a conductor drift very slowly,but the charge travels much faster than the electrons themselves.Kind of like hitting a tube full of steel balls on the end, the energy is transferred from one end to the other immediately, but the balls themselves don't move very much.

With a different number of valance electrons, it would at first blush appear that the charge would also be delayed somewhat in the steel wire compared to the copper wire.

So I am talking about electricity,in the common sense.

OK, in both cases we're talking about electricity, until the magnet stops moving relative to the wire.

But, although I can't prove it, I still say different metals conduct electricity at different speeds. Don't ask me to state the relative speeds through different metals.

I'm not that smart.

Good answer Lyn, each material has a distinct permitivity. This results in each one having its own speed of "light" in the medium. So yes, that's a no.

True,but if you remove the magnet rapidly,the magnetic field in the steel wire will reverse polarity due to back emf,and it will retain residual magnetism,whereas in the copper,it will disappear as soon as the power is removed.

The back emf in the copper is absorbed by a compensating coil and wasted as heat,and reduces arcing of the brushes.

In effect,you are using the back EMF to create power instead of wasting it,like a flyback transformer in and old TV.

This residual magnetism of the steel, could,theoretically,be used added to the following boost the reversed polarity field by proper spacing(mica thickness) of the commutator slots and the result would be less heat and improved efficiency.

Welcome to 2024.

[Sigh] By moving a permanent magnet you create an electrostatic field. This is how permanent magnet generators work.

Electrons flow in a conductor at a considerably slower velocity than the electric field. The multiple classes of study you need to discuss the points you ask are far beyond the scope of an engineering blog.

Ok, I understand that,and it was a very poorly worded question on my part.

Consider a copper coated steel wire with an electric current flowing through it.

Will the magnetic field and electric field have the exact same phase relationship as if it were pure copper wire of the same dimensions?

No! There are tons of information on the web and many, many classes you can attend to properly understand exactly how electrostatic and magnetic fields are inextricably linked together. I am not going to hold your hand answering one misunderstanding of electromagnetic field theory after another. To answer your specific question, the E and B fields will propagate in phase and at the same velocity. They must for even more complicated reasons.

OK.Perhaps after high school I will go into electrical engineering.

This has got my curiosity up.

I don't wish to dissuade you from electrical engineering but electrical engineering only uses these attributes but it doesn't try to explain or understand them. Physics and even cosmology delves into why these attributes exist in our universe. For obvious reasons Physics and Electrical Engineering must understand and use the other's discipline. Regardless of which discipline you choose to pursue in your life, I'm glad that my answers have intrigued you.

Where is the electrical field in a permanent magnet? It appears to exist independently of current flow.I know about the internal molecular alignment required to form a permanent magnet.

About the copper coated steel conductor: Would the steel try to maintain the magnetic field, if alternating, and oppose the next cycle, and try to smooth the changing field?

What would happen if you wound a coil around a strong permanent magnet? Would it act like a weak diode if you applied an alternating current?

I appreciate your patience with my silly questions.

Many E fields reside inside the physical structure of a permanent magnet. An inaccurate but useful analogy of a permanent magnet is the alignment at an atomic level of small electron loops around the nucleus. The net electrostatic charge is zero because the nucleus charge balances the electron cloud charge. So at a distance there is no net E field.

Your next two questions get into electric motor design and are incomplete to answer because of how you posed the question. You do not mention the circuit topology of the E and B field paths. The three dimensional alignment of the components matters. It also matters what current paths and cross sectional areas exist. To accurately discuss this requires a command of three dimensional calculus and vector mathematics. Your high school teachers may have used these terms but I doubt that they require you to be able to do this esoteric mathematics.

As I mentioned in passing, the concepts you are exploring here involve the fundamental Physics of how an electric motor works. If one constructs a conductive coil around a permanent magnet and do not move anything then nothing noticeable happens. However, the insertion or removal of a permanent magnet from a closed loop coil will mechanically require more force than through an open loop coil. The net magnet field around the magnet will also be temporarily changed depending on the coil being an open or closed loop path.

So a coil around an alternating current electromagnet will not act like a diode on the alternating current. A diode is a non-linear device that allows current to flow in one direction and not the other. A coil around an alternating current electromagnet is a transformer. There are non-linear effects that happens in a transformer when one overdrives them but most designs work very hard to not saturate a transformer.

I almost dread bringing this up but you might be looking at a motor with a mysterious coil that prompted your question. There is one way that a diode analogy could be applied with a common coil around the electromagnet of a motor. In a shaded pole motor one of the poles has a closed loop winding around that pole. This winding reduces the magnitude (shades) of the alternating magnetic field produced in that stator pole location in the circular path around the rotor. When the motor gets first turned ON this shaded pole makes an imbalance in the clockwise or counterclockwise forces on the rotor. Thus the motor reliably spins the rotor in one direction at every start up. This does not make a non-linear electric load as a diode in a circuit will. It just puts a bias on the torque magnitudes applied to the rotor.

Not an alternating electromagnet surrounded by a coil, but a permanent magnet surrounded by a coil through which alternating current passes.I realize it would not work exactly like a semiconductor diode,but would it not tend to suppress a similar magnetic field when the polarities matched up,and amplifying it when polarities are opposite,resulting in a decrease in amplitude one cycle half and an increase in the other?Or would it simply produce more hysteresis and heat as a result? Or would it have no effect on the alternating current.

I can see the magnet eventually losing it's field,due to heat build up.

I understand how a shading pole works, in motors and A/C relays but this is not the same thing.

Just curious.

" a motor with a mysterious coil" ? Interesting.Tell me more.Motors are my favorite subject.

The reason I brought up the copper coated steel wire is I saw a tig welder with copper coated steel wire in it, and I wondered what the effect would be if an A/C current were passed thru a coil of it,if the wires had insulation,like motor wiring does. Don't know how to test it though.

I know the wire melts in the welder application,but that is done on purpose with high amps.

Welding wire is copper plated, so the copper is very, very thin. (.0005" or less).

No effect at these frequencies.

<...wound a coil around a strong permanent magnet? Would it act like a weak diode if you applied an alternating current?...>

One would get a magnetic field that varied in intensity and possibly polarity depending on intensity, at the same frequency as the applied electric current.

A diode is the equivalent of an electrical one-way street, in simple terms. There is no way that the above arrangement will create one.

I am an omnivore of information regarding electricity and physics.

I pick up scraps as I go,but they may all fit together eventually.

Perhaps I will pursue a degree in each field.

I don't just want to know how,

I want to know why things happen.

I am like the little kid that is constantly asking"Why". I don't want to grow up and lose that curiosity.

"....

Apply a permanent magnet to the end of a steel wire.Presume the wire is 300,000 meters long.

At the exact same time, apply a voltage to a copper wire, with the exact physical dimensions and length.

Will the magnetic field arrive at end of the steel wire at the same time as the electrons,(and the induced magnetic field) arrive at the end of the copper wire?

..."

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You won't be able to measure the change in magnetic field at the other end of a 300,000 meter length of steel wire even applying the strongest permanent magnet available today.

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But on the other hand, in the 300,000 meter length of copper wire electrons are already there. If you instead were referring to the electrons that were at the other end just before applying the voltage, then assuming there is no low or even moderate resistance return path, the drift speed of the electrons if going to impossibly slow, and your staff for the experiment will retire before electrons drift from one side to the other.

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So the answer is still no, though if you are trying to find out as you describe, you still won't know.

Actually, the answer is yes and no,because if no one is there to measure it,it will be in a state of superposition until it is observed.So the poor charge will be sitting there, marking time, until a sentient being observes the result.
You are correct,the drift of individual electrons is on the order of feet per minute,however the charge moves much faster,but slower than C.
One is correct to presume that charges travel slower or faster depending on the medium of transport.Even light can be effectively "stalled" almost to a stand still in some recent experiments.
The experiment of the OP,as worded, would be impossible to implement with current technology because a perfect magnetic insulator would be required to isolate the steel conductor while the magnet is moved into position.
However, one could induce an electromagnetic field,a single pulse, at one end of each conductor and time the round trip reflection.
This principle is used in TDR meters to measure cable length,or distance to a fault in the cable.
An oscilloscope can be used as a TDR when properly configured.
So, in regards to the OP question, there should be an observable difference in propagation speed between copper and steel conductor,but I would expect a lot more hysteresis in the steel conductor due to excessive eddy currents compared to the copper conductor.
There are many other variables to consider as well,too many for this limited discussion.

You should explore the articles about applying Bayesian statistics to quantum mechanics. They negate the observation paradox thus (pun intended) puts the cat question to rest.

The OP did specify arrival of the electrons at the end of the wire (presumably not the electrons that were all ready there...since arrival requires a change in presence) and did not specify any return path.

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Additionally the OP specified a permanent magnet... not conducive to pulsing.

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I'm sticking with my initial position that the OP will not gain insight through the experiment as he outlined it.

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BTW, I did not recognize you at all with your new picture/icon. It is a good look for you.

There is one thing missing from this discussion... when you apply a voltage to a conductor, there is no movement of electrons. Electrons move when a current flows in the conductor. Raising a conductor to a potential does not move electrons.

Actually, the electrons move very little.The charge moves through the conductor.

And current flow is mentioned in the OP post #10.

An electrical signal moving through coax has a delay of around 30% or more, (depending on type), below the speed of light in a vacuum.

This is why fiber optic signals propagate faster,as well as no capacitive and inductive interference.

A coax cable is equivalent to a long chain of series inductors and parallel capacitors.

Yes, that's transmission line or telegrapher equation theory. Oliver Heaviside did some brilliant work on this a few years ago. A very small amount of current must pass through the conducting wire to charge the parasitic elements that must exist in any real circuit. This is true for any conductor topology not just coaxial cable topology. There are bandwidth advantages to using coaxial cabling that gets into antenna design theory but that's many layers farther down the rabbit hole.

Is it obfuscating or clarifying to use a mixed metaphor in a complex topic?

'...Is it obfuscating or clarifying to use a mixed metaphor in a complex topic?...'

.

I'm assuming that is more of a rhetorical herring and not a herring of a different color.....

....false dichotomy?

Yes.

What'd he say?

_{In reply to the comment about the effect of mixed metaphors, I was raising the possibility that the two suggested outcomes might not be mutually exclusive (and therefor the choices provided would be an example of a false dichotomy).}

_.

_{I wasn't highly certain, so to gather more data, I wanted to employ a mixed metaphor.... and since the original comment and my reply were swerving sharply away from the 'real question'... red herring.}

An insulated conductor will have capacitance when voltage is first applied. When the capacitance is charged, the current flow stops, so there will be an initial current flow thru an open circuit.

<Sigh> No. The "open circuit" condition occurs only after the capacitor is charged to whatever voltage the voltage source provides. Remember, all voltage sources and capacitors are two-terminal devices.

By definition, yes, sources and sinks (two terminals) are needed for current to flow as per Maxwell's equations.

If you apply a stationary magnet to the end of a long steel wire, open circuit, no current flowing, after the initial induced voltage, will the opposite end of the wire become magnetic and stay magnetized as long as the permanent magnet is still on the opposite end?. I know there will be residual magnetism after the magnet is removed.

I know the magnetic field travels down the wire and induces a voltage as it goes, which creates a magnetic field, which induces a voltage, etc. till it decays and stabilizes.

Imagine a DC motor with alternating positive and negative stator coils. When the positive coil is de energized, the field collapses and the collapse causes an inverse polarity on the steel wire, which holds a residual magnetic field which contributes to the next (negative)coil. And the cycle repeats with the next coil. Basically, it uses the flyback voltage to enhance the efficiency and should also reduce sparking at the brushes.

I have not timed it, no. I wont be either

Question:

"Apply a magnet to a steel wire at one end.

Apply a voltage to a copper wire of same diameter and length.

Isolate the wires from each other to avoid any mutual interference.

Will the magnetic field propagate at the same rate as the electron travels?"

Answer:

Since the magnet remains motionless at one end of the steel wire, the magnetic field does not move either. Speed = Zero.

Since the voltage is applied at one end of a copper wire and not a circuit, no current flows and there is no electron movement afaik. Speed = zero.

Summary: zero mph = zero mph

So you are saying that if you apply a stationary magnet to one end of a steel bar, the other end will not be magnetized as a result?

Not what I was taught...

HiTekRedNek-

you said "

So you are saying that if you apply a stationary magnet to one end of a steel bar, the other end will not be magnetized as a result? Not what I was taught.."

correct me if im wrong but isnt M inversely proportional to distance, and at the end of a 300KM wire with no current on it, M will be effectively zero, not measurable, for the strongest permanent magnet.

Whoever said that engineering was an exact field has never visited CR4.

Have we EVER agreed on anything?

I am puzzled by the concept of post 26.

I can visualise touching a permanent magnet to the end of a steel wire, and I guess the 'magnetism' will appear at the far end of the wire (instantly??).

I can visualise touching the positive terminal of a battery to the end of a copper wire, but have trouble with the concept of how the 'voltage' appear at the far end if there is no circuit and no current flow.

And if a circuit is created by connecting the far end to the 'negative', then a current will flow. Is the original wire straight?. Then another 300,000 m will be needed to connect it. Or is it a loop?

How will the speed be measured?. Is it the time the current takes to jump above zero?

Just wondered.

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And if there is a delay would it be longer than the time it is taking CR4 to fix the posting error.

"Could not process form: The system was unable to process this form".

Damned annoying.

The iron wire is composed of magnetic domains, each of which is magnetized in a random direction. Applying an magnetic field from the magnet causes the domains aligned with the field to grow at the expense of neighboring domains. I would expect this process to be a lot slower than the conduction of an electric field through copper.

Why? In both cases one is only influencing the orbital state of a valence electron. In the magnetic case the state change is just a spatial alignment of this orbital.

Why?

It's my understanding that electrical conduction involves electrons in the metal that are not permanently attached to any one atom - more or less a pool of electrons shared by all the atoms. Add some at one end of the wire and some others pour out the other end. All the electrons migrate as long as there is an electric field to move them. (I think we all agree that the electrons themselves actually move very slowly because there are so many of them.)

It's my guess that this is a quicker process than rearranging the magnetic direction of the unpaired electrons in the iron atoms. If you look at the magnetic hysteresis loop, you can see that there is some amount of energy required to move the magnetic domains, and this action needs to propagate down the wire. This is why I think it might be a slower process than electrical conduction.

I don't have any figures to back this up, and perhaps my model is overly simplistic. Just my thoughts on the matter.

You are asking questions that will require a lot reading on your part. You can start with basic electronics, (perhaps at Khan Academy), and then read the lectures of Charles Proteus Steinmetz.

Steinmetz came up with many of the terms and methods used every day today in electrical and magnetic measurement and calculation. RMS readings of AC for an example. Pay close attention to his description of the fields themselves and the "medium" in which they form. He relied on an idea of space called the "aether", which you will also come across when reading Heaviside, Marconi and Tesla as well.

The two fields you are concerned with differ greatly in only one way, and they are intimately connected by this difference alone: Magnetic field lines are closed loops that close upon themselves; Electric fields are Di-electric field lines that terminate at two different points in space.

The speed of propagation of an electromagnetic wave -or the speed of propagation of an electric or a magnetic field- through space is c (the speed of light).Hence, if your "wires" were "made" of vacuum (i.e. a kind of vacuum tubes) the propagation of these two fields should be the same (c).

However, when these fields are travelling through a material other than vacuum, then their speed is decreased. The value of this (decreased) speed depends on the inner structure of the material. [Of course, you are already familiar with this phenomeno: As you may already know, the carrier particle of the electromagnetic field is the photon. And, of course, you know that the speed of photons is decreased when they pass through a material. And this leads to the "refractive index" of the material (which is n=c/v, where v is the speed of light through the material)].

So, as the two fields are travelling through the metalic wires, their speed will be somewhat less than c. If the material of these two wires was the same (e.g. if both wires were made of copper) then the speed of both fields should be the same. However, you have two different materials (copper and steel), so the speed will be different.

Thank you for a very straightforward answer to my question.I presume the speed of the magnetic field through the steel would be faster than the electron charge through the copper wire.Is that a valid presumption?

The propagation time of the electric field through a 'stand alone' copper wire is ≈96% of c. [This time (called 'time-to-flight' in signal integrity) is an even smaller portion of c, if the 'return wire' is nearby and it, also, depends on the dielectric material where the wire lies and -in some cases- even on the geometrical characteristics of the wire.)]

However, it's hard to find the propagation time of a magnetic field inside a steel wire, in order to compare these two situations. (A little searching that I made in the Internet gave no results. If you need to know about this issue, make your own research. And if you get any good info, share it with us.)

Also, in your initial post, you wrote: "…Will the magnetic field propagate at the same rate as the electron travels?..." Beware, of this misunderstanding: Only the electric field propagates in a wire at a speed close to c, not the electrons. Actually, the electrons move very slow, with speeds of -e.g.- some millimeters per sec. (So, if -e.g.- you apply a dc voltage to a lamp through (a few meters long) wires, the electrons of the wires which lies close to the source will succeed to reach the lamp after -e.g.- 1h. However, the electric field reaches the electrons inside the lamp's filament at speed ≈c, forcing them to move and, so, the lamp is turned on almost immediately.)

It was a case of poor wording on my part.I meant to say the "electromagnetic field" when talking about the induced magnetic field, and the "magnetic field" when talking about the field produced by the permanent magnet.

I have learned since that when the magnetic field travels down the conductor, it produces an electric filed,which produces a magnetic field,etc.,etc., and propagates in that manner.So it seems there is no such thing as a pure magnetic field,even if produced by a permanent magnet.The magnetic field from the permanent magnet will travel thru space as a series of collapsing magnetic fields, which produce an electrical field,which produces a magnetic field,which produces an electric filed, etc.When moving through empty space, it travels at C,but when moving through different densities the velocity is lower.I can understand a little better now how difficult it would be to develop a constant for the different materials.

Light refraction is easy to measure, but EM seems to be a lot harder.

However, I would like to conduct some experiments of my own.

Do you know of a supplier of insulated enameled steel wire in standard wire sizes?

Thanks again!

No, I don't know any supplier for steel wires. I'm afraid that you have to do your own research on this issue. Sorry... ...

I am diligently pursuing the subject matter on Google, and have found much interesting information.

I have searched for insulated steel wire,but all I find is Stainless,and very expensive.So I will try a different way.

I remember electric fence from my uncle's farm was steel wire on insulators.

I see no reason why this will not work for my experiment.

If I use equal length and same gauge of wire of each material,and run them in a straight line,and then return back to source,keeping them separated from each other,and from themselves.(A very wide open loop,separated by 3 feet between upper and lower runs). I have enough room for at least 100 feet each way.

In other words, a line of posts with insulators to hold the wire, with a small capacitor (value undetermined at this time) at the end connected from the wire to ground.

The insulators will be immaculately cleaned.

The signal source will be grounded at origin and the positive side connected to the wire.

If I can borrow a fast 'scope,I may be able to time the round trip of a pulse sent down the wire.

I will have to set up the scope outside,at the wires,so that no other leads will interfere with the measurement.

This should reveal the difference if I take care to make certain that all conditions are as close to identical as I can make them.I realize this will not be very accurate, but at least an approximate value.

Any reason why this will not work,at least in principle? Is there some critical factor I am overlooking or don't know about?

I have a couple of questions I think you need to contemplate:

• Why not just put an iron rod inside a copper pipe?
• Does it really have to be a wire with both media in contact with each other?
• In doing your experiment I am curious how you intend to differentiate between the E field and the B field of each method of signal propagation?
• How do you intend to measure the time of flight of these signals?
• A 1 meter foam dielectric cable with a propagation velocity of 81%c will take 2.7 nanoseconds to transit. How long will your steel and copper lengths have to be to produce a measurable difference in transit time?
• How do you intend to produce a magnetic field change without making an electrostatic field change?

Lastly are you aware that many coaxial cables (Belden 9146, 9587, 8241, 8263 to just name a few) already use copper clad steel wire for the center conductor? Belden 9862 uses a copper clad steel center conductor that looses only 9.4 db at 1GHZ after a 100ft transmission.

Until you've mastered Maxwell's equations and understood Oliver Heaviside's telegraphy equations I believe you will just be spinning your wheels getting frustrated trying to perform this test.

My research thus far has shown that you are correct in that there is no difference between the propagation time of electromagnetic versus "magnetic" waves,in fact they are Siamese twins and inseparable.My focus now is to determine the different velocities of emf through different materials,in this case, steel versus copper.I could not find any readily available information on the propagation speed, like is available for coax cable.And coax has a dielectric and metallic shield that will affect the propagation speed.

I intend to separate the two materials,and test them separately.

I read online where a scope can be used to determine the length of a coax cable to the fraction of a foot,and this was an old 100mhz scope.

This should work for my purposes.

You said that some coax cable is steel with a copper coating.If copper is superior,why use steel?Why copper coated? I know signals are low amperage,so why copper at all?

Sorry to be such a nag,and I am sure you are right, I am just wasting my time,but I must do this to scratch my itch of curiosity.Sure beats watching tv.

Steel is used in these cables for the mechanical strength. The copper cladding provides a low resistivity when high frequency skin effects start to happen. The E and B fields generated in a coaxial cable happen in the dielectric material between the shield and center conductor, not the conductors themselves. (A misconception people have about coaxial cable is that they shield from interference. They actually reduce transmission into free space more than they shield.)

There is already a lot of analysis on the propagation speed in coaxial cables. This really was done by Oliver Heaviside over a century ago. A nice "intelligent layman" analysis on coaxial cable velocity from a reputable company.

You ask the right questions. Keep up the work. You will be well rewarded with proper schooling.

Roughly, the velocity of E-M waves in space is 1 nanosecond/foot. If you put a step change of voltage into straight 100 ft length it will take > 100 ns to get to the end where it will be reflected back, taking the same time as outward. So you are looking at >200 ns which can be distinguished with 100 MHz scope, triggered from outgoing step. When the reflection arrives, it adds or subtracts from the outgoing step, if the source has a resistance, and can be timed on scope. You need a fast step or pulse generator. Some computer integrated circuits are good for that.

You could say that suddenly putting a magnet at the end of a wire is the same as suddenly applying a current to a coil around its end.

But it is difficult to get an isolated wire. If you have ground underneath it has an effect. Telegraph engineers soon found it was better to use two wires spaced uniformly on poles than to rely on ground return.

You could compare two steel wires [like baling wire] with two copper wires at the same diameter & spacing.

I really appreciate your clear and concise answers,without all the nay-saying.I hope I have not worn out my welcome.

If so, simply ignore the following:

Is there a constant that can be applied to steel vs copper as pertains to my original question?

At what frequency and voltage (approximately) would the "skin effect" occur?

I realize that electrons like to repel each other,being like charges, so it would mean that high voltage and/or or high frequency would create a skin effect?

It would seem that hollow conductors would be cheaper and lighter if most of the current is carried by the outer layers in certain conditions where weight is an expensive factor, such as spacecraft,etc?

Maybe I have over-thought this subject?

Thanks

"hollow conductors"

Bend a piece of copper tubing, or any hollow tubing.

Report the results.

Rigid wave guides are used in to transmit "current" in the mega/giga hertz range, and the signal travels on the inside.

Another subject altogether.

Consider what will happen if both wires are bismuth or pyrolytic graphite.

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You should reconsider your assertion about the propagation speed being the same if the wires are the same material.

I would suspect that how quickly electrons or charge move down the conductor would be heavily influenced by the material structure. Specifically, lattice structure, grain boundaries, and various inclusions would impede the flow. Pure copper vs a steel alloy? Talk to a metallurgist or a materials scientist about what an electron might see in each material.

When you say "apply a magnet", do you mean the magnet is stationary? If so, then the magnet induces no current, but the current will create a magnetic field. Google Right Hand Rule, electromotive force, and counter-electromotive force.

What do you know! There are no stupid or simple questions. One apparently simple question has gotten a page full of responses from experienced old guys.

If you enjoy thinking about these kinds of questions, you might make a good scientist. If you also like solving practical problems, you might also make a good engineer. Stick around. You can learn a lot here, even if you don't have a clue what's going on most of the time.

Why do AP's post all of these types* of questions?

Oh, no...the magnetic field will propagate faster. The magnetic field knows what the electrons are going to do...so it just obliges by starting out earlier.

or...

The magnetic field has about a .001 nanosecond handicap.

^{_{* Re: stupid}}

Well,

To their (I say "their" because AP is genderless) credit this AP isn't a TPITA*, like most.

*Total pain............................

Ok, let me simplify even further,because I am poor at explaining things. A screwdriver that is not magnetized will not pick up nails or tacks.

Apply a magnet to the end,and hold it there.

The screwdriver will now pick up nails because it is conducting the magnetic field from the permanent magnet which is not moving.Not inducing a voltage,but the magnetic field travels from one end to the other anyway.

Now, remove the magnet, and some of the nails will drop off,and some will remain because the screwdriver has become slightly magnetized.

I presume that the magnetic field from the permanent magnet took some time to travel from one end of the screwdriver to the other.This is the magnetic field to which I refer.

Now, induce a current flow into a copper conductor, and the magnetic field will accompany the electric field down the conductor.

This is the electromagnetic field that I refer to.

My question was answered very simply and elegantly by GK, post#48,so I have my answer,I am simply trying to clear things up for you about the original question.I realize it was poorly worded and explained,and I stated in the beginning that it might be considered a stupid question.Evidently at least one person did not think so.

Thanks,GK.

The problem is, regardless of how simple and elegant you think the answer in comment #48 is, it isn't actually correct.

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Photons don't carry charge. If you were attempting to establish a current through a 'vacuum wire', it would involve a beam of electrons or ions. Either of which both have mass, which should clue you into the fact that even in the vacuum, c won't be reached.

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The reason the propagation of magnetization in a ferromagnetic material will almost always be slower than the propagation of change in voltage in a conductor, is related to a property known as hysteresis.

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That doesn't explain the mechanism, just puts a label on it, so that if you are truly interested, you know what to start reading about.

Thanks to everyone for their valuable insight.GK gave me the answer in his last sentence,even though his explanation may not suit everyone.

The answer has prompted more questions,and I have a lot of study to do to understand why it is so.

I will not bother this forum again until I have done more study and hopefully become more knowledgeable on the matter.If I hit a solid wall, and need help to get over or through it, I will be back.Google is such a rich source of information,almost anything can be found.

I did not mean to exclude anyone in my thanks, for everyone has been very helpful,even the negative answers made me dig deeper.

So my sincere thanks to everyone!

Hi all I have read with interest the answers to the question posed. The general drift of the question is valid despite a lot of nitpicking. We need original thinkers and James Clark Maxwell would have been the sort of person to pose such a thought experiment so don't be put off. The way I would think about it is that as the magnetic field is turned on it would grow via the rotation of the dipoles in the steel as they align with the field. This is not instantaneous unlike the collapse of a field which is very rapid. This is why collapsing fields create large induced currents in coils. In the case of an electric field free electrons in the copper would move towards the positive end of the wire and this shuffling would create a potential from one end of the wire to the other once the electrons at the end had moved up. So one relies on atomic rotation and the other on electron flow. Doesn't LEC and MAG refer to this as the permeability (magnetic) and permativity (electric) of a given material. I am sure the answer lies in Maxwell's equations but its been a long time since I studied them. A guess is pretty useless but I would bet on the magnetic field for what its worth. You have provoked thought and discussion keep it up.

This has been a facinating read and I appreciate all the comments given.

In special relativity, electricity and magnetism are the same thing.