Can the light create electromagnetic field?

[scientist91]

I will be very happy if you answer me. I tried several times on google to search about this but I didn't find anything. So please answer me, if you know the answer. Thank you.

 

[Danger]

Light is an electromagnetic field. It is simply our way of identifying the visible (and near-visible) segment of the EM spectrum. There are several arbitrarily defined segments such as microwave, radio, X-ray, gamma, IR, etc.. Light is generally considered to be the part that we can see.

 

[scientist91]

Light is an electromagnetic field. It is simply our way of identifying the visible (and near-visible) segment of the EM spectrum. There are several arbitrarily defined segments such as microwave, radio, X-ray, gamma, IR, etc.. Light is generally considered to be the part that we can see.

Is it field?

 

[Danger]

This isn't my area, so I can't give you a definitive answer. Essentially, though, yes; it is an electomagnetic field propogated by photons. If I understand it correctly, it is in fact 2 fields. One is electric, the other magnetic, and they travel together but oscillating at 90 degrees to each other. Someone more knowledgeable really has to take over from here.

 

[pmb_phy]

Is it field?

Yes. There is one and only one difference between, say, and EM wave at microwave frequencies and that of a red beam of light is the frequency of the waves. They are exactly the same in physical properties and makeup.

Pete

 

[DaveC426913]

Yes. There is one and only one difference between, say, and EM wave at microwave frequencies and that of a red beam of light...

Well... two.



One of them does a lovely job on my bag of Orville Redenbacher's..

 

[Danger]

If the last commercials that I saw were any indictation, the microwaves had far more effect upon Orville's bag than just popping his kernals.

 

[scientist91]

If you say that the light is field, then I will make electromagnetic induction with light and get current in closed circular loop.

 

[ZapperZ]

If you say that the light is field, then I will make electromagnetic induction with light and get current in closed circular loop.

And you do! People who work in designing accelerator cavities have to deal with wall currents due to the the changing B fields. That is why you have lossy material.

Zz.

 

[scientist91]

And you do! People who work in designing accelerator cavities have to deal with wall currents due to the the changing B fields. That is why you have lossy material.

Zz.

Can you give me some link or picture?
So let's conclude the light is electric and magnetic field, right?

 

[ZapperZ]

Can you give me some link or picture?
So let's conclude the light is electric and magnetic field, right?

As I have mentioned earlier, please READ and STUDY the Hyperphysics link I gave earlier, especially on electromagnetism. You would not have to "conclude" such a thing if you had spent time doing that.

Zz.

 

[pmb_phy]

If you say that the light is field, then I will make electromagnetic induction with light and get current in closed circular loop.

Due to the high frequency of a light wave the light would not be able to penetrate inside a conductor. Same thing with x-rays.

You wanted a picture, right? Draw a picture of an EM wave and you have by neccesity drawn a picture of light.

What part of "Light is an EM wave" don't you understand?? Its a pretty simple idea.

Pete

 

[scientist91]

Due to the high frequency of a light wave the light would not be able to penetrate inside a conductor. Same thing with x-rays.

You wanted a picture, right? Draw a picture of an EM wave and you have by neccesity drawn a picture of light.

What part of "Light is an EM wave" don't you understand?? Its a pretty simple idea.

Pete

Look man, if you say that the light is both part of magnetic and electric field, then, the photons "are moving" (so the magnetic field is moving), so it will produce current inside the conductor, right?

 

[Xezlec]

Look man, if you say that the light is both part of magnetic and electric field, then, the photons "are moving" (so the magnetic field is moving), so it will produce current inside the conductor, right?

It does produce a current. YES. Light does produce an electric current in any conductor it hits. Indeed.

But light has a very high frequency. So because the frequency is so high, the "electrons in the conductor can't move fast enough". So the current is very very very very small.

That's an oversimplification, but I don't know what else to say that will be understood.

 

[scientist91]

It does produce a current. YES. Light does produce an electric current in any conductor it hits. Indeed.

But light has a very high frequency. So because the frequency is so high, the "electrons in the conductor can't move fast enough". So the current is very very very very small.

That's an oversimplification, but I don't know what else to say that will be understood.

Why the electrons can't move so fast when the magnetic field of the light is moving so fast? Practically, when you move magnetic field faster, so the electrons in the conductor are moving faster, so the current is stronger.

 

[ZapperZ]

Why the electrons can't move so fast when the magnetic field of the light is moving so fast? Practically, when you move magnetic field faster, so the electrons in the conductor are moving faster, so the current is stronger.

1. The electrons are in a conductor, i.e. a medium. There are other things in their way!

2. Electrons have MASS. EM field does not.

Zz.

 

[lightarrow]

Why the electrons can't move so fast when the magnetic field of the light is moving so fast? Practically, when you move magnetic field faster, so the electrons in the conductor are moving faster, so the current is stronger.

Suppose you are pushing a child in a swing. Let's say you give a push every two seconds, to increase its amplitude. What would happen if you gave a push every tenth of second? The swing wouldn't move much. Make the experiment.

 

[scientist91]

Suppose you are pushing a child in a swing. Let's say you give a push every two seconds, to increase its amplitude. What would happen if you gave a push every tenth of second? The swing wouldn't move much. Make the experiment.

I think you have wrong understood it. Look, I made that experiment. So if I push with 0.1sec (with same power) when I will get to 2 sec (0.1*20) so the swing's moving speed will be so fast, 20 times more then once in 2 seconds.

 

[Xezlec]

It's hard to explain in such simple language. Pick up a spring. Hold it by one end. Move it up and down slowly. Now try moving it faster, and faster, and faster. Eventually the spring won't bounce very much anymore because you're shaking it too fast. It can't keep up.

Electrons have mass, and they also have other things "holding" them. They are stuck in a "soup" of other electrons, so they can't just move as fast as you want.

 

[scientist91]

It's hard to explain in such simple language. Pick up a spring. Hold it by one end. Move it up and down slowly. Now try moving it faster, and faster, and faster. Eventually the spring won't bounce very much anymore because you're shaking it too fast. It can't keep up.

Electrons have mass, and they also have other things "holding" them. They are stuck in a "soup" of other electrons, so they can't just move as fast as you want.

But man, when you practically moving magnet among conductor, it will induce current inside of the conductor. When you move the magnet very fast so the electrons are moving very fast, right?

 

[Mentz114]

The electric and magnetic field components of light are oscillating very fast. This means they reverse their direction too quickly to move the electrons any distance. The situation has been explained in the earlier posts.

When an radio antenna picks up a signal, it is responding to the oscillating electric component of an EM wave - essentially low frequency light.

 

[Xezlec]

But man, when you practically moving magnet among conductor, it will induce current inside of the conductor. When you move the magnet very fast so the electrons are moving very fast, right?

You are not moving it "very fast" compared to light. The fields in a light wave oscillate hundreds of trillions of times per second. If you can move your magnet that fast, the electrons will stop keeping up with you.

 

[scientist91]

So, when you move the magnet very fast among conductor in closed circular loop you create stronger current. But what will happen if the light wave oscillate hundrets of trilions times per second? The electrons will not move, but why?

 

[rbj]

So, when you move the magnet very fast among conductor in closed circular loop you create stronger current. But what will happen if the light wave oscillate hundrets of trilions times per second? The electrons will not move, but why?

you're not listening. whether you are generating light (or any other E&M field) or receiving such a 'transmission", electrons (or some other charged object) are, at least in a probabilistic sense, moving back and forth. even at trillions of Hz. eventually frequencies get so high that matter doesn't have much ability to deal with it. i think your DNA would get messed up if you were exposed to enough gamma or cosmic radiation.

but 91, you just need to accept that visible light is just another set of frequencies in the broad EM spectrum. that's what several other people are trying to confirm to you.

 

[scientist91]

you're not listening. whether you are generating light (or any other E&M field) or receiving such a 'transmission", electrons (or some other charged object) are, at least in a probabilistic sense, moving back and forth. even at trillions of Hz. eventually frequencies get so high that matter doesn't have much ability to deal with it. i think your DNA would get messed up if you were exposed to enough gamma or cosmic radiation.

but 91, you just need to accept that visible light is just another set of frequencies in the broad EM spectrum. that's what several other people are trying to confirm to you.

Can understand what actually happens with the electrons. They must move when there is presence of magnetic field, so when you move the magnet very frequently you get current, still I can't understand, what actually happens when there is presence of light with high frequency.

 

[lightarrow]

Can understand what actually happens with the electrons. They must move when there is presence of magnetic field, so when you move the magnet very frequently you get current, still I can't understand, what actually happens when there is presence of light with high frequency.

As we are trying to make you understand (I tried with the example of the swing but I had no success!), since electrons have a non-zero mass and so have inertia, if you try to move them with an oscillating force which frequency is too high, they cannot follow the movement of the force; just because of their inertia, at the time they have started moving in one direction, the force has already changed direction, so they don't have time to follow its movement. Try to figure it out.

But notice, you would have the same exact situation with every object with non zero mass, accelerated with a force with constant amplitude but increasing frequency: in the simpler case of a free object, the amplitude of its oscillations decreases as the force's frequency increases.

 

[scientist91]

As we are trying to make you understand (I tried with the example of the swing but I had no success!), since electrons have a non-zero mass and so have inertia, if you try to move them with an oscillating force which frequency is too high, they cannot follow the movement of the force; just because of their inertia, at the time they have started moving in one direction, the force has already changed direction, so they don't have time to follow its movement. Try to figure it out.

But notice, you would have the same exact situation with every object with non zero mass, accelerated with a force with constant amplitude but increasing frequency: in the simpler case of a free object, the amplitude of its oscillations decreases as the force's frequency increases.

Ok now I understood it, but I have one more question, are the electrons moving in conductor (with current), moving like they move in nuclei (spinning)? When they are excited and gain energy and unbound from the atom, they release the excess of energy?

 

[Sojourner01]

No. For a start, you've got this muddled:

When they are excited and gain energy and unbound from the atom, they release the excess of energy?

Electrons in atoms release energy when they drop through energy levels. They absorb energy to gain energy levels, and eventually dissociate entirely.

Even so, this isn't what happens in a conductor. Electrons in metals move as though they are free, even though they are in fact still in the potential of the nuclei. This property is what makes metals metallic; this is what metallicity is. The mechanics of this are complicated and I don't fully understand them myself, suffice to say it's to do with the periodic nature of the nuclear potential wells.

 

[scientist91]

No. For a start, you've got this muddled:



Electrons in atoms release energy when they drop through energy levels. They absorb energy to gain energy levels, and eventually dissociate entirely.

Even so, this isn't what happens in a conductor. Electrons in metals move as though they are free, even though they are in fact still in the potential of the nuclei. This property is what makes metals metallic; this is what metallicity is. The mechanics of this are complicated and I don't fully understand them myself, suffice to say it's to do with the periodic nature of the nuclear potential wells.

So they release the excess of energy but how? Or they don't release the excess of energy?

 

[Sojourner01]

What excess of energy?