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#101
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Question about "Another look at reflections" article.
On Jun 1, 5:44*pm, K1TTT wrote:
no, it is not obvious. *where do you draw the line... 1 degree, .1 degree, .001 degree? *at what point is the angle small enough to say that they have 'interacted' and the energy is redistributed? I don't know the answer but zero degrees (perfect collimation) will result in interaction. i propose that 'cancellation' is just a special case of interference where the waves are 'close enough' to collinear that you never see the interference pattern. When b1 = s11*a1 + s12*a2 = 0 at an impedance discontinuity, wave cancellation has taken place. s11*a1 and s12*a2 are coherent sine waves, equal in magnitude, and 180 degrees out of phase. Have you read the FSU web page where they describe wave cancellation? All these concepts are old hat to optical physicists. micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/ waveinteractions/index.html "... when two waves of equal amplitude and wavelength that are 180- degrees ... out of phase with each other meet, they are not actually annihilated, ... All of the photon energy present in these waves must somehow be recovered or redistributed in a new direction, according to the law of energy conservation ... Instead, upon meeting, the photons are redistributed to regions that permit constructive interference, so the effect should be considered as a redistribution of light waves and photon energy rather than the spontaneous construction or destruction of light." -- 73, Cecil, w5dxp.com |
#102
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Question about "Another look at reflections" article.
On Jun 1, 11:31*pm, Cecil Moore wrote:
"... All of the photon energy present in these waves must I suggest that you immediately dump any reference that includes a phrase like "photon energy present in a wave". There is a wave theory of light, and there is a particle theory of light, and these two theories do not play well together. 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. ....Keith |
#103
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Question about "Another look at reflections" article.
On Jun 2, 3:31*am, Cecil Moore wrote:
On Jun 1, 5:44*pm, K1TTT wrote: no, it is not obvious. *where do you draw the line... 1 degree, .1 degree, .001 degree? *at what point is the angle small enough to say that they have 'interacted' and the energy is redistributed? I don't know the answer but zero degrees (perfect collimation) will result in interaction. what is the physical mechanism for 'interaction' that requires perfect collimation? i propose that 'cancellation' is just a special case of interference where the waves are 'close enough' to collinear that you never see the interference pattern. When b1 = s11*a1 + s12*a2 = 0 at an impedance discontinuity, wave cancellation has taken place. s11*a1 and s12*a2 are coherent sine waves, equal in magnitude, and 180 degrees out of phase. Have you read the FSU web page where they describe wave cancellation? All these concepts are old hat to optical physicists. micro.magnet.fsu.edu/primer/java/scienceopticsu/interference/ waveinteractions/index.html "... when two waves of equal amplitude and wavelength that are 180- degrees ... out of phase with each other meet, they are not actually annihilated, ... All of the photon energy present in these waves must somehow be recovered or redistributed in a new direction, according to the law of energy conservation ... Instead, upon meeting, the photons are redistributed to regions that permit constructive interference, so the effect should be considered as a redistribution of light waves and photon energy rather than the spontaneous construction or destruction of light." -- 73, Cecil, w5dxp.com coming from a 'primer' and containing words like 'somehow' doesn't raise my confidence in the explanation. |
#104
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Question about "Another look at reflections" article.
On Jun 2, 10:33*am, Keith Dysart wrote:
On Jun 1, 11:31*pm, Cecil Moore wrote: "... All of the photon energy present in these waves must I suggest that you immediately dump any reference that includes a phrase like "photon energy present in a wave". There is a wave theory of light, and there is a particle theory of light, and these two theories do not play well together. 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. ...Keith agreed. photons are good when working with other elementary particle interactions to represent the em energy lost or transferred during particle interactions. they are not that useful when studying wave propagation or interaction with macroscopic object... including 1/4 wave coatings. |
#105
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Question about "Another look at reflections" article.
On Jun 2, 6:39*am, K1TTT wrote:
On Jun 2, 10:33*am, Keith Dysart wrote: On Jun 1, 11:31*pm, Cecil Moore wrote: "... All of the photon energy present in these waves must I suggest that you immediately dump any reference that includes a phrase like "photon energy present in a wave". There is a wave theory of light, and there is a particle theory of light, and these two theories do not play well together. 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. ...Keith agreed. *photons are good when working with other elementary particle interactions to represent the em energy lost or transferred during particle interactions. *they are not that useful when studying wave propagation or interaction with macroscopic object... including 1/4 wave coatings. For those who may be interested, Richard Feynman offers an introductory lecture on photons he http://vega.org.uk/video/subseries/8 It illustrates that attempting to compute 1/4 wave coating behaviour with photons would be extremely tedious, though possible. On the other hand, at low light levels, where individual photons become discrete events, the wave theory becomes completely inadequate. Fortunately, for practical applications, power levels are much higher than this and the wave aproach is quite useful. ....Keith |
#106
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Question about "Another look at reflections" article.
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. 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." 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. 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. 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 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. 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. 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". http://www.teachspin.com/instruments...eriments.shtml I, personally, am not interested in getting the right answer using the wrong concepts. And I am absolutely sure that your math models do not dictate reality. It is supposed to be the exact opposite. -- 73, Cecil, w5dxp.com |
#107
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Question about "Another look at reflections" article.
On Jun 2, 5:37*am, K1TTT wrote:
what is the physical mechanism for 'interaction' that requires perfect collimation? The impossibility of divergence. That collapsed probability function can occur in an RF transmission line and in an interferometer. Secondary effects, e.g. noise, are obviously ignored. coming from a 'primer' and containing words like 'somehow' doesn't raise my confidence in the explanation. The "somehow" means that even if someone doesn't comprehend enough to have "confidence in the explanation", that lack of confidence will have zero effect on the real-world outcome - the energy involved in destructive interference wave cancellation will be preserved through constructive interference based on the conservation of energy principle. Please feel free to prove them wrong. -- 73, Cecil, w5dxp.com |
#108
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Question about "Another look at reflections" article.
On Jun 2, 5:39*am, K1TTT wrote:
photons are good when working with other elementary particle interactions to represent the em energy lost or transferred during particle interactions. *they are not that useful when studying wave propagation or interaction with macroscopic object... including 1/4 wave coatings. Photons are useful for proving that EM waves must necessarily travel at the speed of light in the medium. Photons cannot stand still - therefore, EM waves, known to consist of photons, cannot stand still - therefore any overly-simplified mashed-potatoes version of energy stored in an RF transmission line violates the laws of physics. -- 73, Cecil, w5dxp.com |
#109
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Question about "Another look at reflections" article.
On Jun 2, 1:39*pm, Cecil Moore wrote:
On Jun 2, 5:39*am, K1TTT wrote: photons are good when working with other elementary particle interactions to represent the em energy lost or transferred during particle interactions. *they are not that useful when studying wave propagation or interaction with macroscopic object... including 1/4 wave coatings. Photons are useful for proving that EM waves must necessarily travel at the speed of light in the medium. Photons cannot stand still - therefore, EM waves, known to consist of photons, cannot stand still - therefore any overly-simplified mashed-potatoes version of energy stored in an RF transmission line violates the laws of physics. -- 73, Cecil, w5dxp.com wave function solutions to maxwell's equations are enough to prove that for me. |
#110
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Question about "Another look at reflections" article.
On Jun 2, 8:57*am, K1TTT wrote:
wave function solutions to maxwell's equations are enough to prove that for me. Not a loaded question: How do Maxwell's equations applied to a standing wave prove that the component forward and reflected waves are moving at the speed of light in the medium? If it can and if I can understand it, I wouldn't need to use the photon argument. -- 73, Cecil, w5dxp.com |
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