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My electrical weakness

  1. Mar 26, 2004 #1
    Ok, I am a Physics major so far and am getting a little nervous about my choice. I am struggling with my second calculus-based physics class which is electromagnetism. If I am having a difficult time with this subject am I doomed to fail in physics in general. I did fine with mechanics, I just have a hard time understanding the nuances of Maxwell's equations and how to apply them. I realize the importance of the subject matter for later classes and that's what worries me. Anybody else struggle with this topic or should I start looking for a different major.
  2. jcsd
  3. Mar 26, 2004 #2
    infraray posted: "Anybody else struggle with this topic (E&M) or should I start looking for a different major."

    Stick with it; I had the same experience.

    For me the problem was that I was just beginning to feel like I sort of, maybe, kind of understood div, grad, curl and all that in my math class. But at the same time that's ALL I saw in my physics class. I don't know if this is the source of your frustration, but I wouldn't be surprised. Vector calculus is hard!

    But learning it is well worth the effort, if for no other reason than being able to understand classical electricity and magnetism.

    If you think about the things you learned in your mechanics class, a lot of them were, at least qualitatively, predictable. The physics made them quantitative, but you sort of knew how things were going to come out.

    But all kinds of totally unexpected things pop out of Maxwell's equations. Like electromagnetic waves propagating at the same speed as light!. And just wait til you see how the magnetic field pops out of the electric field if you assume that the speed of light is always the same. It's pure magic!

    Good luck!
  4. Mar 26, 2004 #3

    Doc Al

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    Just a guess, but I've probably been struggling with E&M since before you were born! Don't give up quite yet--it's worth it.

    If you need help, you've come to the right place.

    (If it's the vector calculus that's got you nuts, you may find this book helpful: "Div, Grad, Curl and all that" by H. Schey. Check your school library.)
  5. Mar 26, 2004 #4
    Div, Grad, Curl is a great book. I'm reading it now.

    Don't give up. Keep plugging at it.

    I'm a second year student physics. I'm the opposite, the mechanics in the first course kicked my tail. The EM in the second course was easy for me but I can see how that can be trouble.
  6. Mar 26, 2004 #5

    Dr Transport

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    I nearly flunked E&M my first year in college. I worked like a dog to learn enough to pass the course and final exam. I did a little bit better as an advanced undergraduate, nearly aced the graduate course, now I work in Electromagnetics in industry. Keep working on it, my old prof said "if you can learn E&M, you can learn any field theory out there".
  7. Mar 29, 2004 #6
    I thank everyone for the encouragement. I was hoping I was not the only one who felt this way about EM. Our next chapter is optics so I am ready for a break from EM, maybe that's all I need. Thanks again.
  8. Mar 29, 2004 #7


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    I got a "C" in this course when I took it. I've been a physicist for almost 20 years now. As JFK said, "...we choose to do these things because they are hard."

  9. Mar 29, 2004 #8


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    Having read everyone's terrific responses, I guess here's my 2-cent worth...

    One of the major difficulties in E&M is the mathematics. You will need to know 2nd order differential equations, special functions, fourier transforms, etc...etc. More often than not (and I've said this already in some other strings), it is the mathematics that bogs down the understanding of the physics. You have to know how to do all those spherical harmonics/Legendre polynomials/Bessel functions, etc just to solve for all those boundary conditions.

    The problem is made worse in many schools (at least, here in the US) when the students are forced to learn the mathematics at the same time they are learning the physics. This is true also in QM - there is nothing more daunting than to come across the word "orthorgonal" for the first time in, of all places, a QM class, for example.

    One solution here is to have the necessary mathematics BEFORE one actually enrolls in such classes. Unfortunately, this means that one may have to delay many of the physics course till one has "enough" mathematics, and most physics majors simply do not have the patience or resources to do that. It is why a typical physics student simply does not have enough mathematics by the time he/she enrolls in an E&M or QM class (typically 2nd semester sophomore/Junior level).

    Some schools have started offering a class in mathematical physics. Unfortunately, most of these are seldom designed for students who had just had intro level calculus. They are typically meant for more advanced undergraduates, and they also used texts such as Arfken that requires a more sophisticated knowledge level. So this doesn't help much either for students about to jump into E&M and QM classses.

    What I HIGHLY RECOMMEND is that you get this text:

    Mary Boas "Mathematical Methods in the Physical Sciences" (Wiley).

    This text is meant for students at the sophomore level who has had at least basic calculus. It, and the accompanying Students Solution Manual (sold separately) is meant for self-study, and she is quite verbose in her explanation of each topic. In the solution manual, she TELLS YOU why she is solving the problem one way and not the other. The book covers all the basic mathematics tools that one would need in various undergraduate physics/engineering courses. The chapter on Calculus of Variation alone is worth the price of the book. She also doesn't bore you with the gory details of the derivation of the mathematical principles. She simply tells you how to use it, when to use it, and for what limits is it valid. For a physics/engineering major, that's all we care about in mathematics.

    I have recommened this book to many students, and all of them have found it extremely useful. I hope this may solve some of your difficulties with E&M.

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