What ACTUALLY causes a magnetic field to be generated when there is a current?

[DeShark]

Well, in order to explain correctly what is magnetism, you need relativity. Math is a bit hard, but the concept is easy:

Coulomb's law is only valid for electrostatics. When you move a charge, part of the electrical field is "transformed" to magnetic force. It's like the components of a vector when you rotate your referential, part of one component is transformed into another component.

So, in essence, electricity and magnetism aren't as far apart as it sometimes seems to be when you look at the equations.

Haha, yes, but why does the electrical force transform into a magnetic one? (I guess you could answer all sorts of things about "If it doesn't, the universe is not subjective", causality probably breaks down, whatever). I quite like those symmetry based arguments and because mathematics has dealt nicely with symmetries for some time, we can stand on the shoulders of mathematicians to see a lot more. But nothing explains WHY those symmetries exist really. It's all going round in circles. You ask one question, you get another.

 

[vaibhav1803]

quit the math people its real simple to explain from a change of frame...
suppose you are the standing in the lab observing currnt flow through a wire,we'll call this POV the lab frame.
let the electrons point-of-veiw be the e-frame
now in the e frame at any point which is at rest for the electron there will be an electric field
the same point moves in the lab frame at the avg. speed of the electrons in the comductor.
try finding these two field through maxwells laws
then proceed with a similar approach for a point at rest in lab frame.
for the explanation to why it occurs..there are many versions to it already presented by out peers the simplest explanation being that it happens because of a change in frame, we need to ensure that in both frame the same amt. of energy/power must pass through the "VICINITY" of that point in either frame if the system is isolated.

 

[vaibhav1803]

Haha, yes, but why does the electrical force transform into a magnetic one? (I guess you could answer all sorts of things about "If it doesn't, the universe is not subjective", causality probably breaks down, whatever). I quite like those symmetry based arguments and because mathematics has dealt nicely with symmetries for some time, we can stand on the shoulders of mathematicians to see a lot more. But nothing explains WHY those symmetries exist really. It's all going round in circles. You ask one question, you get another.

i agree but wouldn't it be better to have a take that symmetries exist for the sake of have least possible value of interaction energy?
(i am no scholar on this topic(just outta high school) rather this is but a random guess from generally obseved phenomenon.)

 

[Phrak]

Haha, yes, but why does the electrical force transform into a magnetic one?

Has it transformed? Or has the coordinate system of the observer transformed?

 

[brainstorm]

Magnetism occurs when electron motion aligns among multiple atoms/molecules, correct?

Wouldn't it then make sense that a linear transmolecular electrical current would cause the electrons involved to align?

In other words, left to their own random motion, the electrons could orbit in random directions, but when they are driven by force/current to transfer the force linearly, they respond with the path of least resistance, which is the direction that the charge is moving.

This could possibly be likened to a shopping cart with 4 wheels that can pivot freely in 360 degrees. left alone, the wheels could all pivot in different directions from one another. But when the cart is pushed, the wheels respond by aligning in the direction of least resistance. Of course, shopping cart wheels have axels and atoms seem more like floating ball bearing that can rotate in any direction freely. Nevertheless, it makes sense that they could/would align according to transfer of linear force/energy.

This makes sense to me, anyway.

 

[vaibhav1803]

I wish to Quote the multipole theorem, from what brainstorm has said,
thenet mag. field is the result of multiple "multipoles" self aligning in a certain direction causing this "magnetic field" due to moving sets of multipoles and think of it thi way,
suppose u keep an electron near the wire and can deterministcally(just assume) find where it is, u see that it moives with a certain velocity/acceleration now follow the elctron in a fromwhere you see its at rest, what do you see..?
the electrons motion is normal to the wire..which directly implies a "fast moving" electric field which on applying correct frame transforms you will see as the one proposed by biot savart law.
anyone agree...?

 

[brainstorm]

the electrons motion is normal to the wire..which directly implies a "fast moving" electric field which on applying correct frame transforms you will see as the one proposed by biot savart law.
anyone agree...?

What does "normal to the wire" mean? What does "fast moving" mean? In contrast with "slow moving?"

 

[vaibhav1803]

the reply isn't genuine its just a theory I am proposing, i am yet to get down to the transform equations(just out of high school need some time)
normal to wire as in if u released an electron u kept beside the wire, you would observe that the e- in a complex way moves towards the wire, but if u move in a reference frame attached to the electron you see that the motion is only approaching the wire(normal/perpendicular to its length), due to a force occurring as a combined effect of various microfields in the wire which when correctly transformed gives you the magnetic force. that's what i propose

 

[DeShark]

I wish to Quote the multipole theorem, from what brainstorm has said,
thenet mag. field is the result of multiple "multipoles" self aligning in a certain direction causing this "magnetic field" due to moving sets of multipoles and think of it thi way,
suppose u keep an electron near the wire and can deterministcally(just assume) find where it is, u see that it moives with a certain velocity/acceleration now follow the elctron in a fromwhere you see its at rest, what do you see..?
the electrons motion is normal to the wire..which directly implies a "fast moving" electric field which on applying correct frame transforms you will see as the one proposed by biot savart law.
anyone agree...?

"u" "thi" "deterministcally" "elctron" "fromwhere" "moives" "thenet" "mag." all crop up in my spellchecker as incorrect. I actually cannot read this.

In a reference frame in which the electron is at rest, it doesn't move normal to the wire. It is at rest, by definition. Electric fields don't move. If you're going to quote a theorem, it should be a well-known one. A search for "multipole theorem" in google returns about 19 results, this thread is the third one.

I don't want to put you off doing physics or contributing to this board, but please run your posts through a spellchecker and read over them before submitting them. There's an edit button too in case you make a mistake and notice it later.

 

[DeShark]

the reply isn't genuine its just a theory I am proposing, i am yet to get down to the transform equations(just out of high school need some time)
normal to wire as in if u released an electron u kept beside the wire, you would observe that the e- in a complex way moves towards the wire, but if u move in a reference frame attached to the electron you see that the motion is only approaching the wire(normal/perpendicular to its length), due to a force occurring as a combined effect of various microfields in the wire which when correctly transformed gives you the magnetic force. that's what i propose

Lorentz transformations can also be used to prove that magnetic and electric fields are simply different aspects of the same force — the electromagnetic force. If we have one charge or a collection of charges which are all stationary with respect to each other, we can observe the system in a frame in which there is no motion of the charges. In this frame, there is only an "electric field". If we switch to a moving frame, the Lorentz transformation will predict that a "magnetic field" is present. This field was initially unified in Maxwell's concept of the "electromagnetic field".

The theory I think you're driving at has already been proposed by Maxwell and taken further by Einstein. You should take a look at them both (maxwell's equations and einstein's special relativity), since they're both incredible feats of the mind; really inspirational.

 

[vaibhav1803]

"u" "thi" "deterministcally" "elctron" "fromwhere" "moives" "thenet" "mag." all crop up in my spellchecker as incorrect. I actually cannot read this.

In a reference frame in which the electron is at rest, it doesn't move normal to the wire. It is at rest, by definition. Electric fields don't move. If you're going to quote a theorem, it should be a well-known one. A search for "multipole theorem" in google returns about 19 results, this thread is the third one.

I don't want to put you off doing physics or contributing to this board, but please run your posts through a spellchecker and read over them before submitting them. There's an edit button too in case you make a mistake and notice it later.

Ah yes, my apologies ,its that i get a bit excited when a of ideas cross my mind(which it did in this thread), which shows up as you tried to read, spellchecker, well let me handle that part,
well the "multipole theorem" is just an idea I am proposing of how to think of the beginning of a mag. field, nothing more nothing less, that instead of 1e- roaming around we have packets of e- buzzing within the wire,im still workin on the math, no I'm not going to see any papers till i really need them, i usually don't refer to the literature, becuse its cheating in the game that i play.
as far the reference frame goes, don't be so skeptical, it was meant to be said the the wire approaches the e- normal to its own length.
as far as putting me off physics goes, fella u can't even come close to it, science the love of my life, and better not mess in that area.

incase you sincerely can't figure out, e- is being use to replace electron in writing, i don't hope u need this. X}

 

[ireland01]

Here's a question for you: Why is there SOMETHING and not NOTHING? Think about it!