Recent content by xxxyyy

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    Polarization of EM waves is preserved after reflection/refraction -- Why?

    In chapter 7.5 Jackson assumes it (pag 218, "all the electric fields are shown directed away from the viewer"). He actually discards the first boudary condition, saying it gives nothing... It is satisfied, and that's good, but, as Feynman said, we need to prove that this is the only solution...
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    Polarization of EM waves is preserved after reflection/refraction -- Why?

    I'm sorry I have to bring up again this discussion but I don't get why from isotropic boundary conditions it's so easy to conclude TM/TE "conservation" upon reflection/refraction. Apart from that, here, in Feynman's lectures https://www.feynmanlectures.caltech.edu/II_33.html below Fig. 33-6, he...
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    Proper Lorentz transformations from group theory?

    Hi, I was looking at this derivation https://en.wikipedia.org/wiki/Derivations_of_the_Lorentz_transformations#From_group_postulates and I was wondering 1- where does the group structure come from? The principle of relativity? or viceversa? or what? 2- why only linear transformations? I remember...
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    EM wave/radiation from which equations?

    Does wave phenomena arise from the third term in Feynman equation (21.1)? At the end of 21-3 paragraph, Feyman boldy says that the complete theory of (classical) EM is in that box... but why doesn't he include the solutions of the homogeneous equations (the wave solutions)? Is really everything...
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    EM wave/radiation from which equations?

    Hi there, in Feynmann's lectures, (Vol 2 eq (21.1) Heaviside-Feynman forumla) https://www.feynmanlectures.caltech.edu/II_21.html it is said that radiation comes from the last term, the one with acceleration in it. This formula is a particular case of the Jefimenko equations, the ones derived...
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    Is Coulomb's law valid in a non-inertial frame?

    Hi, I was wondering, if the charges do not move in a non inertial frame and I don't move too in this frame, will I see the same Coulomb force, some fictitious forces and radiation coming from these static charges? Thanks!
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    B Doppler effect in moving medium?

    Hi there, here's the problem: There's a sound, with a certain frequency coming, from a source. Both the listener and the source are fixed in a inertial reference frame. But there's wind blowing from the source to the listener. Now, this situation isn't the same as the listener chasing the...
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    B I need a template for a report on an experiment -- where can I find one?

    Hi, I have to do an exam (lasting 3 hours) where it is required to perform a very simple experiment. The test is graded, obviously, not on the experiment itself but on how you compile a report on it, tables, graphs, error proagation, data analysis, etc... all stuff I'm definetely not good at...
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    Free inclined plane and a block sliding on it

    Hi, I'm missing something really stupid here... The problem is the usual one with a block sliding down (or moving up, it should be the same) a frictionless inclined plane,which itself is free to move on a orizontal frictionless surface. These problems are usually solved stating that only...
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    Polarization of EM waves is preserved after reflection/refraction -- Why?

    Hello, here's my question: during the usual derivation of Fresnel's equations, it is assumed that an incident EM wave (plane monochromatic) is transverse electric or magnatic and that it keeps this nature after reflection and transmission. How can this be proven? Thank you!
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    I Take a limit in this 2 equation system of 1st order ODEs

    Here are just simple images. https://ibb.co/vsqnJW3 https://ibb.co/yNMNgK3 and here the exact solution (if I didn't do any mistakes...) of the system for c1, (1.18), don't bother with the other junk. https://ibb.co/pRDxKhc
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    I Take a limit in this 2 equation system of 1st order ODEs

    Hello, I'm having a problem with this system. Ignore the physics. I have the feeling it should be tremendously easy... but I can't figure it out. I don't know how to extract it from the pdf so I'll post just the these 2 pages. https://ufile.io/39ovq The equations are (1.14) and (1.15), the...
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