Electric charge flow in AC and DC

[Drakkith]

What do you mean?

 

[Nihad Nazmul]

Maybe I messed up energy and current together. Now I have the conclusion. Glowing a light bulb current has no role and it is done by electromagnetic magnetic field .

 

[Drakkith]

Maybe I messed up energy and current together. Now I have the conclusion. Glowing a light bulb current has no role and it is done by electromagnetic magnetic field .

As with most things, it isn't quite that simple and I'm afraid that we've reached the limit of my knowledge in this area. Just consider that power, which is energy transferred over time, can be find by: P=VI, where P is power, V is voltage, and I is current. In other words, the amount of energy transferred over time is equal to the product of the voltage times the current flow. So I'm not sure I'd say that current has no role in causing a light bulb to glow.

I hope I haven't managed to lead you astray. Perhaps someone with more knowledge than myself can take over from here.

 

[CWatters]

Maybe I messed up energy and current together. Now I have the conclusion. Glowing a light bulb current has no role and it is done by electromagnetic magnetic field .

The filament heats up because electrons collide with metal ions. So the current is important.

 

[Nihad Nazmul]

Electromagnetic field transmits energy. As electromagnetic field acts in quanta that means photon. Then glowing up of bulb filament easily can be explained. Filament produce radiation when photon collide with electron (in filament orbital) and electron completes the Bohr's quantum jump . In glowing the bulb maybe current doesn't interfere . But electromagnetic field depends on current that means flow of electron. So, the more electron the more work therefore the more energy.Note that I may have mistakes.

 

[sophiecentaur]

I will never ever use the word "photon" rather electromagnetic field. Okay, now come to my problem "I couldn't specify one thing that why electrons and current ( flow of electromagnetic field) flow inverse ? Perhaps I've got a reason . That direction of electric field and its push that means force is inverse, the equation F=(-e)E is the precision. " There may have more reason for this .

This is a problem that many people have but it is not a real problem. The Conventional Current was a concept which was used long before anyone had an idea of the existence of electrons. Electric current was just some quantity - a substance, of a sort, that could (and still can) be treated as a fluid that flows according to Potential difference ('downhill'). Someone chose a Sign for the connections on a standard battery (or on a piece of insulator that had been rubbed with something) and that choice was adopted universally and classical electromagnetic theory was developed using this convention. It is all perfectly consistent, with Current flowing from + to -. A long time later, the particle that conveys charge in metals were discovered- the electron. You can just accept this and there is no problem with the fact that these charge carriers happen to have a negative charge. Negative charges flowing one way will correspond to the positive charges flowing the other way. (If you look at solid state Physics, you can have electrons flowing one way and holes flowing the other - that's fine. Also you could imaging positrons flowing in a 'wire' made up of 'Anticopper' and then students would have no problem. (Ignore the practical problem of actually producing a wire of Anticopper!)
Personally, I think it is a very bad idea to try to include what electrons do, in questions of simple circuit behaviour. Electrons in a semiconductor junction or a thermionic diode will behave in a way that you can get your head around. Electrons in a piece of metal are just not amenable to any treatment that relates to your average resistor network. It is not a copout to refuse to use electrons - it's just a pragmatic thing that tells us it is not worth the aggravation and that there are better ways of analysing things. If you don't agree with me then I would ask you whether you would seriously want to consider the way a random gas of electrons flows around a piece of copper when you want to predict its behaviour when you stretch it mechanically. I think you would agree that it is a level too far down for any useful understanding.

@Drakkith - I just got back from a short trip or I would have got stuck in here sooner. You seem to be doing fine, aamof.

 

[Nihad Nazmul]

Drakkith already cleared this.I also think that conventional current flow is nothing but a garbage of past . Actually, I was trying to figure out what actually happens about electricity. Surprisingly, I had to receive the info. that electromagnetic field transmits energy instead of electron. It's a crucial truth that average percent of people still believe it . Gradually, my misconceptions are going away . Now ,I have a clear view actually what happens when a battery attached light bulb glow up . But " Electrons those create current flow are supplied by battery?" I think the answer is yes . Because of charge separation the electrons flow from positive terminal to negative terminal of battery through the wire along the electric field direction. These moving electron has magnetic field which is perpendicular to the electric field. Besides the distributed surface charges have electric field parallel to the internal electric field . The combination of both electric and magnetic field results in electromagnetic field. So now we have electromagnetic field that can easily transmit energy from battery to globe with light speed. Therefore the energy used to glow up the bulb. The radiation of the bulbs filament not only produced by that electromagnetic field but also dipole radiation. The radiation of the bulbs filament ( consequence of Bohr's quantum jump) caused by electromagnetic field .We have to remember this electromagnetic field created by current. The conclusion is glowing of bulb depends on current.
Note: Don't forget to confirm me.

 

[Drakkith]

I think you're about as close to the truth of the matter as you're going to get in this thread.

 

[Nihad Nazmul]

I thought I've already known the real fact . But ,are you saying something more I need to explore? What is that?

 

[sophiecentaur]

Bohr's quantum jump

It is not a 'quantum jump" as in the Bohr atom because it is happening in condensed matter and not just a single atom. I really think you should read (or re-read) a decent textbook, now that you have a number of correct ideas about all this. Your problem is that you are not joining them up in a coherent way. Asking a whole random selection of questions is not the best way to get on top of this. You need a structure for your knowledge and one cannot build one on ones own (unless one is exceptionally gifted - like Max Planck). I have a feeling that, even if you were to get answers to this particular list of questions, you would simply come up with another set. Try to approach this in the conventional way and it will deal with questions, one at a time, and in a formal way. It really does work very well for other people, you know.

PS My view is that there is never any answer to the question "What is 'really happening' here". It's just a set of layers of a model which need to be cleared, one at a time, rather than trying to delve too deeply into a few localise regions of a subject.

 

[Dale]

But what is the role of electromagnetic field?

As Drakkith said, the field transports the energy. Are you familiar with the Poynting vector and Poynting's theorem? I think that would be the next thing for you to explore.

In an AC or DC circuit, such as those you find in residential wiring or household appliances, energy is not transported by the current inside the wires. Instead, energy is transported by the fields outside the wire.

 

[zoki85]

In an AC or DC circuit, such as those you find in residential wiring or household appliances, energy is not transported by the current inside the wires. Instead, energy is transported by the fields outside the wire.

In other words, an electrical energy is transported through the insulators, not through the conductors. Quite shocking but true

 

[sophiecentaur]

SO steer clear of live spaces!

 

[Nihad Nazmul]

I know Bohr's quantum jump doesn't act main role here . But it happens in a little quantity with other radiations. As electromagnetic field transmits energy I brought that in description . My random question was for messing up current and energy transmission and maybe for the reason questions have stopped peeking. It is true that what really happens can't be watched by shooting camera ? But ,explaing reasons real fact can be depicted and models do that. I was trying to understand by applying models. @sphiecentecur

Yeah,I have idea about poynting vector .Energy transmits by electromagnetic field as electromagnetic wave and the quantity of energy in area per unit is called poynting vector. The direction of energy is perpendicular to that electromagnetic wave . In a battery attached light bulb, from battery converted energy transmits through poynting vector by electromagnetic field of surface vacuum in wire. @DaleSpam

That is why Arnold Sommerfeld (1952) has pointed out, metals are good conductors of current but nonconductors of energy. Metals conduct current but space conducts energy and the best conductor of electromagnetic energy is the vacuum! @zoki85