Electromagnetic wave HD

[jethomas5]

This is the traditional way to show the wave but it is too simple. It graphs the electric field and the magnetic field along points on a line. But electric fields are scalar. They don't have a direction, except for the gradient. For the picture to make sense you would need to show enough of the surrounding radiation to see the gradient. That would be a lot more complicated.

[jethomas5]

This is not the only way it can go. This is linearly polarized light. Circularly polarized light looks very different. Circularly polarized light is the sum of two different linearly polarized waves that are out of phase. Some people say that this means that linearly polarized light is fundamental and everything else is combinations of that. But I think linearly polarized light is the sum of two different circularly polarized waves that are out of phase too. So which is more basic?

[jethomas5]

This is a traditional visualization of one way an EM wave could go while fitting Maxwell's equations. There might not be any such thing as EM radiation, maybe it's all some kind of weird particles, but Maxwell's equations do fit the data at least as well as Newton's equations fit relativity.

[LOLipopz28]

This is so cool! I am a kinesthetic learner, but I visualizing stuff like this really helps, also. Thanks a lot! I am going to take my physics final tomorrow... EEEEEEEKKK! Thank you for making this vid, though. This will really help. :0)

[MohammedHammady]

روعة

[sinachiniforoosh]

not very interesting...

[IQ20000Berta]

@sinachiniforoosh that's you, you are a EM Wave

[sinachiniforoosh]

@IQ20000Berta I'm not saying that EM waves are not interesting, I'm talking about the video, besides, I'm not an EM wave, I emit them.Now maybe you can say that I'm a wave whose wavelength is inversely proportional to my momentum by a factor h, but that's not an EM wave, that's a matter wave.

[IQ20000Berta]

@sinachiniforoosh if you know what matter is, you are the new canditade for the next 10 physic nobelprices in a row. Nobody knows what matter really is. What is an electron proton quark and so on. Your EM Wave Information is a dancing cloud through the space till it is eaten up by the dark matter.

Everything is a mystery, but good to have the maxwell and einsteins equations, they explain our world a little bit.

[sinachiniforoosh]

@IQ20000Berta I didn't say that I know what matter is, you're right about the mysteriousness of everything, I just say that according to what I know from physics right now, it's not very accurate to say I'm an EM wave, hm?

[theroadnomad]

or blender 3D

[coolazga]

can anyone tell my what software for doing this animation please ? thnak y ou

[culturacolombia]

@coolazga I'm guessing any 3d software will do . 3d studio max , studio 4d , maya etc .

[z1zaz]

Your first question reveals as high a lack of understanding as is illustrated in this video.

Tesla was not wrong.

Maxwell's did not explain what EM radiation was, only provided calcs for its generation.

EM radiation is NOT a wave ! Nor are there any tansverse components !

This 'wave' error arose due to inadequate understanding of the young Hertz when explaining the findings resulting from his single turn resonant loop detector.

All EM radiation is photons - spin related energy packets.

[z1zaz]

Okay, please animate a longitudinally polarised EM wave ?

[TopGunMan]

Can someone who truly understands this explain why the magnetic and electric fields of an EM wave are in phase, even though maxwell's law states that an oscillating electric field produces a magnetic field with the highest magnetic strength at the greatest rate of change of the electric field intensity. (out of phase)

[j0lin101]

@TopGunMan In case you have not seen the explanation yet. It says: curl(B) = dE/dt + J. Which means greatest curl, not greatest strength. Curl is a function of spatial derivative of B. So greater curl means B varies more in space (ie dB/dx ), which happens in the same place as greatest dE/dt, so they are in phase.

[CACBCCCU]

@j0lin101 Nice explanation. Thank you.

The E and B vectors point laterally, perpendicular to direction of light propagation, and oscillate at the wave frequency at a stationary point, spin 1 in that only full lateral-plane instantaneous rotation brings it back. In gravity the vector will point in the opposite direction of propagation and does not normally oscillate in any direction, hypothetical gravity waves being an exception oscillating laterally with bilinear symmetry, a spin-2 property.

[TopGunMan]

@j0lin101 Ah yes I was stuck on this problem for a few weeks until I found out that the actual law uses a curl, which they don't really say in first year calc-physics. Very frustrating.

[z1zaz]

@TopGunMan

Does the transverse magnetic EM 'wave' component exist in the first place ?

Your comment is valid for a resonant circuit; but magnetism is a reciprocal *concept* only !

Tesla-1919-

"The Hertz wave theory of wireless transmission may be kept up for some while, but I do not hesitate to say that in a short time it will be recognised as one of the most remarkable and inexplicable abberations of the scientific mind which has ever been recorded in history."

Some 'short' time; Hey ?

[mike4ty4]

@z1zaz "Some 'short' time; Hey ?"

Yeah, Tesla was wrong. So what? Maxwell EM won.

[mike4ty4]

@z1zaz Anyway, what's the point of a longitudinal EM wave? Even if it were possible to use, it would not seem to offer any advantage. You can "beam" as much power as you want through space, the only trouble is that if your intensity is really high (like if you want to transmit town power or something), you'll cook people. Why would longitudinal waves be non-interacting? *Anything* with a charge interacts with EM fields, that's what "charge" means! ATOMs have charges in 'em, so...

[z1zaz]

@mike4ty4

You have already witnessed the outcome of high power longitudinal EM radiation at one very well known event - only likely you did not realise it was the cause of what we all saw.

[mike4ty4]

@z1zaz Where was that?! I've heard of accusations of this kind for several different events ("Tunguska", 9/11, etc.), none of which have at all been proven to have been caused by any such things (e.g. Tunguska was just a cosmic impact, 9/11 was a fire in a really damaged building, etc.).

[z1zaz]

@mike4ty4

Tesla, Moray, Le Bon and I think Keen all discussed the possibility for molecular EM dissociation before 1920!

Moray was knocking birds out of the sky before WW2, just like recent reports in the US!

watch?v=uxLz1v_hfaQ

Those poor people at the Tower tops were disrobing/ falling because they and the building were heating up

- in a beam!

Stating that EM radiation is a 'wave' with 'transverse field components' is just another lie!

It is photons which affect electron orbits/ bonds.

[mike4ty4]

@z1zaz

1. Birds falling was due to fireworks concussion -- mechanical waves, not electromagnetic waves

2. EM waves heat things up -- that's a proven fact (just go out in the sun!). I don't know why that's so important to mention here, other than it highlights an obvious safety problem with "beaming" lots of power all over the place.

[mike4ty4]

@z1zaz 3. How's your "longitudinal wave" interpretation any better?

[z1zaz]

@mike4ty4

You are asking me about something which does not exist.

EM radiation is NOT waves.

HOW TO PROVE THERE IS NO MAGNETIC FIELD COMPONENT TO EM RADIATION

Use a 4" ferrite rod antenna to feed an AM radio at 1MHz.

Then 8" of same diameter - better reception.

Then 16" - no better = no magnetic EM component energising ferrite!

ONLY EM PHOTONS GENERATING COIL CURRENT !

Make a room sized 1MHz magnetic field using an giant inductor

Now the larger the ferrite rod the greater the coupling!

[z1zaz]

@TopGunMan

Check out Wikipedia - Hertz - EM wave.

Hertz's original standing EM 'wave' observations are exactly as you describe,

and not as illustrated here.

It is the resonantly induced magnetic flip which casts off the EM photon radiation from within the antenna conductor(s).

[maaszaxxs1]

cool but is there any video on engineering electromagnetics, tht is too basic

[MrRobotoToo]

Here's an applet that provides much better visualizations of EM waves: wwwDOTfalstadDOTcom/emwave1/

Obviously, just replace each DOT with a period.

[mygoditsfullofstarz]

this is not a good visualization of an EM wave....it doesnt show the wave actually propagating through space

[JFSwifty]

I dont understand why this is wrong, it show the electric wave moving on 90 degrees to magnetic wave ? please Expalin

[sparcer1]

physics 2

[addadhdnarc]

Isn't that how "QAM-PSK" is handled or am I way off?

[Slav4o911]

No the wave is not moving like that, this animation is not correct.

[junior00bacon00chee]

this is not what an EM wave looks like.....

these amplitudes merely represent quantities along a vector....it is a purely mathematical representation of something no one on the planet understands.

in reality no one knows that EM "looks" like, since it carries light signals. in order to hypothesize what it looks like you would have to create a qualitative physical model which presents the actual shape of EM.

[r8448]

Why are they in phase? Isn't there a 90° phase delay time between the two?

[CACBCCCU]

That's a great question, r8448. I have thought the same thing.

The H field is apparently ignored in most applications, and having E and H out of phase apparently would make total photon energy a constant, which is apparently an assumption of quantum physics (Energy = hf, f constant frequency) so I suspect you may be right.

[r8448]

It seems like nobody really knows for sure. The question is then, how can EM-waves travel trough vacuum. Are there electrons in vacuum? There is currently a need for (moving) elektrons to create a H field.

[CACBCCCU]

It doesn't seem that one has to consider electrons in the vacuum to answer the question of photon E-H phase relations.

As I mentioned before, the amount of heat generated in a flat absorber is presumably not phase-dependent under heating by a phase-coherent beam of photons. For example a 400 nanometer laser would heat a chunk of powdered coal equally as well from one inch away as it would from one inch plus 100 nanometers distance.

[CACBCCCU]

The same observation of fixed laser heating rate over various distances would presumably apply to, say for example, a 100 nanometer thick sheet of gold sandwiched with graphite and carbon dust, to limit the total absorber distance from the 400 nanometer laser output port to a precise range.

[r8448]

@CACBCCCU

Too complicated for me. Besides when you involve quantum physics in the story, then it's just like a never ending story with all those new particles besides electrons. Gauge boson and the likes.

[CACBCCCU]

r8448, we're talking about light here, and sure light is made of bosons, and that's a reference to quantum physics, but light quanta (EM quanta) are the only quanta of interest here, the energy of each light quantum (photon) is quite low compared to the total energy of an electron. The generation and detection of light are where electrons definitely come into the picture, so I'd suggest using laser heating to keep the picture simple, much like the relation between photon energy and frequency.

[CACBCCCU]

r8448, if you prefer, let's just use Maxwell's equations and forget about experiment:

Using the modern Heaviside form of Maxwell's equations in the vacuum or a chargeless medium, del cross E is proportional to the rate of change of the magnetic field B, and del cross B is proportional to the rate of change of the electric field E. So it seems that if the incident beam is in free space, it apparently should have the E and B fields 90 degrees out of phase with each other.

[CACBCCCU]

After writing that, I had to go look it up in one of my old books on electromagnetism, and apparently if one goes through all the math properly, using Maxwell's equations, the E and H fields are indeed correctly shown to be in phase in this video.

Sorry about the confusion, it's been a long time since I've looked closely at this subject.

[maaszaxxs1]

@CACBCCCU isn't del cross B equal A, so that divergence of B should be equal to zero, Maxwell's four elementary eqns

[CACBCCCU]

@maaszaxxs1 - Sorry, it's been about 30 years since I took my last course in electromagnetics and I apparently haven't thought about it enough since then. I think del cross B for light is supposed to be proportional to the derivative of the E field with respect to time, with Maxwell's current-based contribution set to zero, but I've probably got that wrong.

[CACBCCCU]

"There is currently a need for (moving) elektrons to create a H field."

I'm told an oscillating E field generates an oscillating H field. I'm also told the E field and H fields are not in phase at a transmitting antenna.

Seems the photon energy confusion I generated here could be resolved for example by viewing each photon as being something analogous to at least a co-moving half-cycle of the moving wave shown in this video, not just one thin slice of the wave in space and time.

[CACBCCCU]

I'm not sure how one would measure variations in the magnetic field from an electromagnetic quanta, but I suppose the heating energy of a laser beam on a thin nonreflecting absorber should not vary by phase with distance, so again it seems the E and H fields are out of phase so as to maintain the vector sum magnitude constant, and also that both fields are converted into heating energy with equal efficiency.

[lndeo]

А разве волна движется так, как палка?

Помоему, правильнее было бы нарисовать как последовательно растет синусоида, так чтобы сами пики не двигались..

[saleall]

great. tnx