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On Jun 2, 8:00*am, Cecil Moore wrote:
On Jun 2, 5:33*am, Keith Dysart wrote: I suggest that you immediately dump any reference that includes a phrase like "photon energy present in a wave". If you (and others) will give up on the ridiculous concept of EM wave energy standing still in standing waves, I will not have to refer to photons again. Refering to photons is just fine. Just do not mix them in with wave theory. Honor the technical fact that EM forward waves (with an associated ExH energy) and EM reflected waves (with an associated ExH energy) are always present when standing waves are present and that those underlying waves (that cannot exist without energy) are moving at the speed of light in the medium back and forth between impedance discontinuities. Standing waves are somewhat of an illusion and according to two of my reference books, do not deserve to be called waves at all because standing waves do not transfer net energy as required by the definition of "wave". In short, it is impossible for EM waves to stand still. Quoting one of my college textbooks, "Electrical Communication", by Albert: "Such a plot of voltage is usually referred to as a *voltage standing wave* or as a *stationary wave*. Neither of these terms is particularly descriptive of the phenomenon. A plot of effective values of voltage, appearing as in Fig. 6(e), *is not a wave* in the usual sense. However, the term "standing wave" is in widespread use." From "College Physics", by Bueche and Hecht: "These ... patterns are called *standing waves*, as compared to the propagating waves considered above. They might better not be called waves at all, since they do not transport energy and momentum." All quite orthogonal to the original point, but your point about standing waves is quite correct, they are not really waves at all. But your need for the reality of underlying waves is quite excessive. The voltage and current distribution on a transmission line can be solved with a set of differential equations which satisfy some boundary conditions. There is no mention of forward and reverse waves in this solution. Turns out though, that the solution can also be factored in to a forward and reflected wave and this technique will provide the same answer. It does not make these waves any more real. I bring you back to a previous question which you have never answered... On an ideal line with 100% reflection, there are points where the current and voltage is always 0. Knowing that if either current or voltage is 0, power is also 0, how does energy cross these point? And if I cut the line at all the places where the current is zero, it does not alter the energy distribution on the line one iota. How can this be if energy is travelling from end to end on the line? Technically, RF waves *are* light waves, just not *visible* light waves. All the laws of physics that govern EM waves of light also apply to RF waves. PHYSICS has long given up on the idea of waves being an explanation for light. The wave theory fails miserably when illumination levels drop to the level that individual photons are being detected. Though of course the earlier approximate models (waves) are still useful when intensity is high enough, just as we still use Newtonian mechanics to solve many every-day problems. You might like to try http://vega.org.uk/video/subseries/8 for an exposition on the strangeness of photon. That you find it inconvenient for your "mashed- potatoes" theory of energy arguments is not a good reason to abandon the photonic nature of EM waves. There you go again... mixing up you models. EM waves are analog and in no way encompass the quantum nature of photons. It is actually a good reason to keep it in mind and abandon the mashed-potatoes energy arguments as human conceptual constructs that cannot exist in reality. Most of the energy in an EM wave is kinetic energy. Therefore, it cannot stand still. There seems to be some misapprehension here. No one has claimed that EM waves stand still, though you may have been confused by the word 'standing' in 'standing waves'. But then earlier in your post you quote 'College Physics' about 'standing waves', so it is not clear where your confusion originates. There is a wave theory of light, and there is a particle theory of light, and these two theories do not play well together. If they are both correct, they should play well together. If there is any conflict, quantum electrodynamics wins the argument every time. They are not both correct. QED aligns with many more observations than does the wave theory. Another reason not to mix them. While in many situations they will yield the same answers, it is not permissible to mix the concepts from each. Distrust the conclusions of any exposition which does so. Actually, distrust the wave theory if it disagrees with QED. Quantum ElectroDynamics has never been proven wrong. And the wave theory does disagree with QED at low levels, while at higher illumination levels QED agrees with the wave theory. So feel free to prove that standing waves can exist without the underlying component traveling waves traveling at the speed of light in the medium. Feel free to prove that EM wave cancellation does not "redistribute energy to areas that permit constructive interference" as the FSU web page explains. Feel free to prove the Melles-Groit web page wrong when they say such has been proven experimentally. In fact, the interferometer experiment described here proves that reflected EM waves, traveling at the speed of light, exist along with the necessary energy. Take a look at the "non-standard output to screen". And yet known of this aligns with the photons being part of the wave theory of light. They two theories remain distinct. http://www.teachspin.com/instruments...eriments.shtml I, personally, am not interested in getting the right answer using the wrong concepts. Well, (and I am sorry, I can not resist), there is some evidence to the contrary. See: http://www.w5dxp.com/energy.htm http://www.w5dxp.com/nointfr.htm ....Keith |
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