Recent content by Vapor88

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    Magnetic field of a dipole (Griffiths 5.33)

    Wait, I'm still not seeing this. Wouldn't that leave -(m \cdot \widehat{r}) \widehat{r} = -m_{r} \widehat{r} and -(m \cdot \widehat{\theta}) \widehat{\theta} = -m_{\theta} \widehat{\theta}
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    Magnetic field of a dipole (Griffiths 5.33)

    Okay, so if I set it up like this, everything is the same except the coordinate system. So I get -(m \bullet \widehat{r}) \widehat{r} = -m cos ( \theta ) \widehat{r} -(m \bullet \widehat{\theta}) \widehat{\theta} = m sin ( \theta ) \widehat{\theta} ...I don't know why the \bullet or hats...
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    Magnetic field of a dipole (Griffiths 5.33)

    Homework Statement Example: Problem 5.33 Show that the magnetic field of a dipole can be written in the following coordinate free form: Homework Equations http://teacher.pas.rochester.edu/PHY217/LectureNotes/Chapter5/LectureNotesChapter5138.jpg...
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    Magnetic flux of rectangular loop w/ wire

    Homework Statement Find the magnetic flux of the rectangular loop. Show that \int B x dl is independent of path by calculating \oint B x dl Homework Equations The Attempt at a Solution First step was to solve for B from the wire, I did that using Biot-Savart Law for a...
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    Potential from a Quadrupole using Legendre polynml's

    I used the binomial expansion, not the Taylor expansion... They are different, right?
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    Potential from a Quadrupole using Legendre polynml's

    What am I planning on integrating? lol... I'm not really sure, I'm very, very shaky on these legendre polynomials, they're completely new to me, but everyone else in my class is familiar with them. Anyways, I see from there, when plugged into the potential equation, I get an r^-3, which is...
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    Potential from a Quadrupole using Legendre polynml's

    P_{0} = 1 P_{1} = cos ( \theta) P_{2} = \frac{3cos^2 ( \theta) - 1}{2} I'm fairly confident that this is correct. Are these my P_{l} values? And would a^2/r^2 be Pm? Does this mean that I'll have three integrals, all evaluated from -1 to 1, such that \int P_{l}...
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    Potential from a Quadrupole using Legendre polynml's

    Ok, here's what I know of Legendre plynml's from my notes They are integrals such that \int P_{l} (x) P_{m} (x)dx = 0 When l =/= m When l = m, that integral is equal to \frac{2}{2l+1} For this problem, I want to take x to be cos(theta)? Does that turn the first two terms...
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    Potential from a Quadrupole using Legendre polynml's

    Alrighty... After banging my head on the desk, I've got the following. V = \frac{q}{4 \pi r \epsilon_{o}} [- \frac{a^2}{r^2} + \frac{3a^4}{4r^4} + \frac{3a^2}{2r^2} cos^2( \theta)] Now... to implement those Legendre polynomials.
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    Potential from a Quadrupole using Legendre polynml's

    It's not, but I keep reworking it and get that. here is the work for how I got there [1 - \frac{1}{2} ( \frac{a^2}{r^2} - \frac{a}{r} cos( \theta)) + \frac{3}{8} ( \frac{a^4}{r^4} - \frac{2a^3}{r^3} cos( \theta) + \frac{a^2}{r^2} cos^2( \theta))] Then you add that to...
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    Potential from a Quadrupole using Legendre polynml's

    Ok, so I believe this is correct, however, I'm still stumped as far as legendre polynomials go. I have no idea how to implement them. V = \frac{q}{4 \pi \epsilon_{o} r} * [ - \frac{a^2}{r^2} + \frac{3a^4}{4r^4} + \frac{3a^2}{4r^2} cos^2( \theta)] Given this, I can...
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    Potential from a Quadrupole using Legendre polynml's

    For [1 + \frac{a^2}{r^2}- \frac{a}{r} cos( \theta)]^{-1/2} I expand to get [1 - \frac{1}{2} ( \frac{a^2}{r^2} - \frac{a}{r} cos( \theta)) + \frac{- \frac{1}{2} (- \frac{1}{2} - 1)}{2!} ( \frac{a^4}{r^4} - \frac{2a^3}{r^3} cos( \theta) + \frac{a^2}{r^2} cos^2( \theta))] Which gets...
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    Potential from a Quadrupole using Legendre polynml's

    Ok, so I got a bit further in the problem, he wants us to use the first three terms of binomial expansion, I only did the first two to get my results above, but they did not need Legendre polynomials. Though I do not know why my answer is incorrect. If I use the first three terms of the...
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    Potential from a Quadrupole using Legendre polynml's

    I just worked further into the problem, tried using that expansion the same way, don't know if I can really do that though. But I took the a^2/r^2 + a/r cos (theta) = x In the end, I did get something over r^3, which makes sense because it's a quadrupole, but I missed the point of the...
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