Recent content by weichi

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    Field due to charge on surface of dielectric

    So I think you are saying that we can assume that the D field is the same on each side. But that would imply that the E field outside the dielectric would be a constant independent of the dielectric constant. And I don't think that's right, because in the limit of a very large dielectric...
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    Field due to charge on surface of dielectric

    It wasn't actually a homework question, but I agree that it sounds like it could be one :smile:
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    Field due to charge on surface of dielectric

    Since no one has responded yet, I will give the reasoning I've come up with for the case of a linear dielectric. We know that the effect of the polarization will be to introduce a bound surface charge density on the surface of the dielectric. Instead of working with the D field and the free...
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    Field due to charge on surface of dielectric

    We have an infinite half-space filled with a dielectric. The other half-space is vacuum. We take a sheet of charge of density \sigma and place it on the surface of the dielectric. What are the D & E fields everywhere? We clearly have D_1 + D_2 = \sigma. But what other equation do we have? Can...
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    Let us assume Feynman was wrong.

    Easily? Can you elaborate? Or post a link to a paper which explains this?
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    Physics Going back to physics, my first love

    I went through the same process a few years ago, and I will be receiving a masters in physics this May. I started school at age 35, so similar to you. 1. As Locrian and TMFKAN64 said, you are going to take a huge financial hit unless you can find a company to pay for school *and* pay you a...
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    Electromagnetic Waves and Fields

    I think there's an aspect of this question that is just semantics, but it's not completely semantics :smile: All (?) of the waves we have direct experience of are mechanical, like your rope example. Also sound waves, water waves. In these cases some material object(s) is *moving*, and we...
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    Need books/articles with proofs of polygonal number theorem

    Wow, quite a coincidence - I just read chapter 3 of Stillwell, "Mathematics and Its History", which mentions this result! He says it was proved by Cauchy in 1813, with a "short" proof by Nathanson in 1987 (Proc Am Math Soc, 99, 22-24). good luck!
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    Circuit with only resistors and multiple batteries

    Do you mean "what side is positive and negative" in the real circuit, or what side should you choose + and - when solving the circuit? If the former - you can't tell until you solve the circuit! If the later - I always choose a direction for the current in each branch, voltage drops in the...
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    Textbooks that cover plane mirror waveguides

    Pozar, Microwave Engineering, discusses these (for finite width). See also Jackson problem 8.3. Not sure of a treatment for infinite width, if that is what you mean.
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    Feynman on visualizaing the electromagnetic field

    There was a question several days ago related to visualizing the electro-magnetic field. I reminded me of a great passage from the Feynman Lectures on Physics. I won't quote the whole thing, but it is in section 20-3, "Scientific Imagination" (unfortunately I don't think the lectures are...
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    Maxwell's Equations: Find Magnetic Field from Curl

    I don't see why working in k-space would require tensors. I also don't think working in k-space would be helpful for this particular problem, but I admit I haven't given it a great deal of thought.
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    Is electromagnetic wave theory correct?

    I didn't say anything about fuzzy :smile:! You would get the sum (superposition as DaleSpam said) of the EM wave and the "pre-existing" magnetic field. This is not the same as saying that the light would get "fuzzy. It means that if you put, say, a light detector in the region then it's...
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    Is electromagnetic wave theory correct?

    But magnetic forces *don't* act on other magnetic forces. As V50 pointed out, they act on *charged particles*. In your magnet example, a better way to think about it is that the magnetic fields from the two magnets are added together, so that the total magnetic field is the sum of the two...
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    Maxwell's Equations: Find Magnetic Field from Curl

    Yes, exactly! The direction (and location) of the current is always changing. Biot-Savart only applies to steady currents. Not sure what you mean about tensors, I don't see a use of tensors here. If you are stuck, why not post what you have so far? Both your solution approach and your...
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