Hi, I have a simple question on the electromagnetic spectrum.

[ChrisHansen2Legit2Quit]

The electromagnetic spectrum is basically one big EM wave broken down by frequency into subsets (visible, gamma, radio, etc)

Electricity via a conductor produces a magnetic field. Well how do you determine the frequency of that magnetic field?

I want to know where the magnetic field (from electric current via conductor) resides on the EMS?

I'm pretty sure it's not visible.

But it can be, can't it. & if visible is just one "form" of radiation, then why can't you use this to produce all other forms of radiation (gamma, x-ray, etc)

Lastly, magnets. A magnet produces a magnetic field. Where does this magnetic field reside on the EMS?

 

[Fabien]

Hi,

Actually, an electromagnetic wave is composed of a magnetic field perpendicular to an electric field. So, to have an electromagnetic wave out of the air from a conductor, you need to have an electric signal in your conductor at the same frequency of the electromagnetic wave you want.
With a DC signal, you will have a magnetic field, but constant, so no electrmagnetic field. And if it would have been, in the spectum it should be at 0.
In other words, a 10MHz electric signal in a conductor could create a 10MHz electromagnetic wave (non visible of course). If you want visible one, you need THz signal, good luck to get it!
If you want X-ray... well, at least unroll your scotch tape, you'll get it!

hope it's clear...

 

[albbg]

Under some (special) conditions an EM field can indirectly cause light emission and also generates frequencies that differs from that of generating signal.

You can, for instance, consider lightning, arcing or corona effect. All of them are visible (corona not always) and they occupy a certain portion of the EM spectrum in the kHz/MHz range even if also DC currents can generate them. Marconi has exploited this effect to transmit the first signals over the air.
However in these cases an high electric field cause ionization of the air around the conductors, so the side effects are due to the motion of the ions. Of course this is not possible if you are considering just a signal travelling in a wire.

 

[BradtheRad]

I went for most of my life with the idea that radio waves have magnetic properties, in addition to being electromagnetic waves such as light rays and gamma rays and infrared, etc.

The term 'electromagnetic waves' fostered my confusion. We do not think of light and gamma rays as being generated by magnetism, nor inducing electric current. We understand they consist of photons.

So I thought radio waves were different. I thought a radio broadcasting antenna gives off a magnetic field, at high frequency, and that field is powerful enough to travel miles to my tv/radio, and induce electric current in the antenna. However, since seeing a few threads at this message board, I realize I had an incorrect concept.

Instead, a radio antenna gives off photons which are similar to light rays and gamma rays and infrared.

Apparently, below a certain power level, the transmitter gives off a magnetic field. However as power is increased, the antenna makes a transition to emitting photons.

This does not mean I understand the process.

 

[ChrisHansen2Legit2Quit]

So I thought radio waves were different. I thought a radio broadcasting antenna gives off a magnetic field, at high frequency, and that field is powerful enough to travel miles to my tv/radio, and induce electric current in the antenna. However, since seeing a few threads at this message board, I realize I had an incorrect concept.

If this doesn't happen, then what does? Because ^^^ is EXACTLY how I understand it, & it's still exactly how I understand it

Gamma, X-ray, Radio, Visible ... they are ALL on the same spectrum. The only thing keeping them apart is frequency.

"You mean if I tune the radio enough, I can get visible light!"

^ is why I posted this question.

I thought visible light only consisted of photons.



So why do we even use the term "magnetic field" if there isn't one? I mean, if these "waves" are photons, then why not just call it the Electrophotonic Spectrum?

 

[Fabien]

The physics for the light is the same for the radio. The radiation is a magnetic field and electric field which oscillate in phase perpendicular to each other and perpendicular to the direction of energy and wave propagation. The Maxwell equations are the same for light or radio... what differ is the energy and the frequency.

 

[albbg]

Photons are the elementary energy packets and they do radiate electromagnetic waves . Maxwell equations apply to them.
Furthermore, due to the duality they behaves as both wave and particle.

 

[ChrisHansen2Legit2Quit]

Photons are the elementary energy packets and they do radiate electromagnetic waves . Maxwell equations apply to them.
Furthermore, due to the duality they behaves as both wave and particle.

I'll give that another 200 years before someone corrects it.

Thanks gentlemen.


I have another question,

You know how we can "pick up" some things with certain forms of radiation vs others. For instance, bones with X-ray or skin with visible light.

Well what does this say about the things that we are picking up in relation to the form of radiation used?

"Resonant frequency" would be an analogy here. I'm just going to use "resonant frequency" for lack of terminology.

If there's no start or end to the EMS, then I'm going to assume it's infinite. & if you discovered another form of radiation, perhaps you could use it to "see" things you've never seen before. -Things that couldn't be seen before.

*If mass & energy are the same thing, then where does radiation reside on the periodic table? ...perhaps just because something has mass doesn't necessarily mean it's matter?

 

[phongphanp]

Somebody had try to control noise , precision , other try general variable in the electron formular . General science is curriculum that need open opinion and the specific one seem walk on the professor path.

 

[phongphanp]

"Comsol" is software for near field and material analysis, the other you can try make communication receiver project.