Faraday's Law of Electromagnetic Induction

Electromagnetic induction - Wikipedia, the free encyclopedia

thanks for that site i have visited there many times but it does not gives my answer

my Question is still there

plz help me out

thanks in advance

Can't help you.

But yet you gave a link to a website. Did you actually read the question or what was contained within the referenced website ? I thought not.

The ability to use Google is useful but also quite dangerous in the wrong hands.

If you read posts 1, 2, and 3 in sequence, you'll see that lyn first offered help. When it was not sufficient for the OP, and lyn felt he couldn't (or wasn't willing to) go any further, he told the poster so.

I'd do the same thing--if I felt I might have lead the OP to expect I could help him, and then realized I couldn't, or didn't have the time, or the patience, or whatever, I'd feel somewhat obligated to let the poster know that. (Especially if no one else has jumped in to try to help.)

Thanks. I appreciate your intervention, but I fear it is wasted. I don't know why I let useless chiggers bait me like that. After post #2, I knew this was going nowhere, and the name really turned me off.

I have a recurring mental image of a 757 banking sharply to the left, just before entering WTC #2, that will live with me forever.

Think I'll just ignore any posters who don't have the intelligence to sign in.

Cheers.

You're welcome! (Hope I don't become a busybody.)

Ok, I'll try.

An electron has an electical charge.

A moving magnetic field creates an electric field.

The electric field created by the moving magnetic field acts on the electrical charge of the electron, tending to make it move (away from the nucleus of the atom of which it is a part).

The force that tends to move electrons (to cause an electric current) is an EMF (ElectroMotive Force).

If your confusion is about "a moving magnetic field creates an electric field", say so, and I'll decide whether I can attempt to explain why. It is a fact that has been demonstrated experimentally.

Maybe try reading the Wikipedia article on magnetism.

Hmm, and it would probably have been more helpful of me to start by saying that a moving electric field creates a magnetic field. (But is is also true, as I stated above, that a moving magnetic field creates an electric field--the moving electric field may just be a better place to start--you can have an electric charge, it is almost always moving (at some level of detail), and thus it creates the moving electric field, which creates the moving magnetic field.)

How good's your maths?

To be fair, this is a bit of a cop-out. It describes the phenomenon - i.e. the 'what', 'where' and 'when' (if you can follow all the funny symbols), but it doesn't expain the 'why'.

Not sure that anyone can tell you that.

Re: To your specific question on "why" Faraday's Law does induce a voltage across a conductor there is a sub-discipline in Physics that appears to explain why. This discipline/model is called Quantum Electro Dynamics (QED).

I don't really know what I'm talking about here, I'm trying to read and intepret some of the words in the Wikipedia articles on QED:

One of the founding fathers of QED, Richard Feynman, has called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron, and the Lamb shift of the energy levels of hydrogen.[1]

and on the Anomalous magnetic dipole moment:

In quantum electrodynamics, the anomalous magnetic moment of a particle is a contribution of effects of quantum mechanics, expressed by Feynman diagrams with loops, to the magnetic moment of that particle. (The "magnetic moment", also called "magnetic dipole moment", is a measure of the strength of a magnetic source.)

--it seems to me that QED is aimed at explaining a different thing, not why a moving magnetic field creates an electric field and vice versa.

Chill - it's all part of the Big Picture.

Don't lose any sleep over it .

Whoever marked this OT did not understand it.

Well, explain it.

Thinking ... please wait.

"not why a moving magnetic field creates an electric field and vice versa."

I think it has to be moving through matter doesn't it? and the electron flow is strictly from the valance electrons if I'm not mistaken.

I think electric and magnetic fields/particles are two sides of the same coin... electromagnetism... and therefore intimately connected... if one moves, so does the other... like the reflection in a mirror.. one left one right

chris

thanks a lot

Has anyone ever actually proven that electrons flow through a conductor?

I've always envisioned them bumping into each other really hard, kinda like those pendulum toys with the chrome steel balls that seem to go on forever once you start them knocking into each other.

Lightning, on the other hand, is definetely free electrons fired up and on a mission.

thank you very much for your concern

i admit that i am bad student who don't understand things easily but i really want to understand the theory that why electrons start jumping, flowing or moving when magnetic field cuts by the conductor AND why they always get a certain direction to flow.what is actually going on in that conductor i mean physically.

please forgive for my weakness

and thanks again in advance

Beg to differ...If you are initiating an electrica currentl in a copper wire (non-magnetic material) with a moving magnetic field, there is no exchange of electrons from the magnets to the copper wire.

What is happening is that the magnetic field is exciting the electons into a higher state of energy in the form of resonant harmonic spin which is transferred down the wire by the outer electrons in the copper molecules transfering the added energy created by the moving magnetic field to whatever is at the end of the copper wire where is it used up in either creating another magnetic field for motors or heat for lighting filaments or radio waves for electronics.

If you'd read the reply carefully, you'd have noticed that Redfred's comments have nothing to do with magnetic fields - he was responding to your question "Has anyone ever actually proven that electrons flow through a conductor?" (which also has nothing to do with magnetic fields).

Understood, but...if electrons move through a conductor, from where does the replacement electron originate?

Conductive materials are conductive because they have an abundance of electrons that can move to outer orbits or shells and then settle back to their original orbits when the source of the energy generating magnet field is discontinued.

Copper makes such a good conductor because it has eighteen electons in it's third shell and only one in it's outer shell which has room for 32 electrons but only one in orbit. It can move 17 excited electrons into the outer orbit when loaded up to maximum conductive capacity.

Silicon, which is a far inferior conductor to copper but much more stable, has 4 electons in it's outer shell with room for 16 and 8 in the second most outer shell so it can only move the 8 out when energized.

If electrons actually came loose from the atoms, then it follows that silicon with it's outer 4 electons would be a better conductor than copper with it's single outer electron.

Unless there's a circuit they won't move (well, some may shuffle up to one end, but as soon as enough charge builds up, they'll stop).

Electrons don't flow from/to a wall mains outlet unless and until you plug a load in and switch it on.

They come from the atoms of the conductor just up stream. At no time does an ion exist in the conductor. (Well theoretically for extremely brief instances in time there statistically must be ions but let's not go there for now.) Remember for a circuit to conduct current there has to be a closed loop.

A static magnetic field does not, it is a changing magnetic field that makes things happen.....

Salam

there is no engineering answer on your question (WHY?)

you may say sobhana allah....

By the way we all like to know why.

The short answer to your question is that there is no known answer to as to "why" this occurs. Researchers know that when this phenomenon occurs that they observe this behavior and can measure the amount of flux generated when a certain amount of current passes through a wire, but at this time there is still ongoing research into the phenomenon of magnetism and why it occurs. This is a physics research question. I remember asking "why" in a beginning calculus class. The instructor answered, "Don't ask why just master the basics first then ask why later. When you can show me you understand the basics, then you can ask why." 5 Calculus courses later, I was still trying to master the "basics".

thank you all very much for your concern i think i am getting the point now.

i am really very great full to you all thanks a lot again.

Has anyone ever taken apart one of those flashlights that you shake back and forth to charge and make the light work?

I've got one. Never considered taking it apart. It's clear, you can see what's inside.

Yeah, several cheap counterfeit shaker flashlights have a coin battery in them.

I think you will find that all of them have coin cells in them - rechargeable ones which are charged by the shaking - just like the wind up ones have rechargeables which are charged by the winding

No, all of the real motion powered flashlights I know of have an ultra-capacitor that gets charged by the dynamo. All LI-ion batteries do have a higher potential energy density than an ultra-capacitor but the charging circuitry and charging cycle chemistry consumes a significant percentage of the energy generated. I've seen fake clear case shaker flashlights that had no wires attached to the "charging" coil and that slug was just a piece of steel, not a magnet.

Fair enough!

you are really asking "What is energy?"

my answer is: a difference of potential in Time.

I think that when the answers are finally found.. we will see that time is basically it.. when we understand time, we will understand space, matter, and energy...

the entropic force, to make two mathematical points equal in time, drives everything... but the way the universe is built... the rules so to speak.. doesn't allow it to happen... not until the 'end of time'.

good luck

Chris

Restart: 06/19/2011 12:40 PM Faraday's Law of Electromagnetic Induction

<QUOTE>

salam & hi to all

its is said that
whenever a magnetic field cuts a conductor
an EMF is induced in that conductor

i want to know why?

what happend in that
conductor which
couses the electrons to flow?

and how
they manage to
flow in a proper direction.

i know its silly but please

thanks in adavance

</QUOTE>

<NEW>

My question is ...

... i donno if this succeeds now ... let's C

the dB₁causes dI₂ that causes dB₂ that minimizes dB₁

if the wires are close (,(' • × '),) the current is opposing

if the wires are appart (, • ')(, × ') then what ... bulls (do like it)

= a question setup failure

the coreless coil has iductivity coz ...

(X1) interactive self-breaking at dI.i < dI.i+1 (current increase)

(X2) interactive self-boosting at dI.i > dI.i+1 (current drop)

(X1) -- is not required in transformers (and is geometry based)

(X2) -- ε.coil - U.R.load = I × (R.coil + R.load) × F.unknown(dt.load , dt.unload)

(X1) -- is a bad magnetic design OR un avoidable (in Fe-mag "core" designgs ... ?yes •.•)

</NEW>

fuzzy questions by: ci139