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Electromagnetism: Ways to study it.

  1. Feb 8, 2010 #1
    Hello to everyone. I'm quite new here and I just wish I have found this site sooner. I am currently enrolled in Physics 2 class (Introductory) and we have just started Electromagnetism. Quite frankly, I am here to ask for some guidance as I am very weak in Physics. The only reason I passed Physics 1 was because my professor was kind enough to lower his passing grade. Now I'm in Physics 2 and truth to be told, I am currently failing due to my abysmal grades in my quizzes and test. However I still have a chance to redeem myself as I have some more quizzes left and a final exam. I am really determined to do well, and I read somewhere that Physics is seeing the "big picture" and once that "big picture" clicks, you will be able to understand it. Is there way or technique this can happen sooner? I solve and solve problems, but I feel I'm just picking out formulas randomly without any deeper understanding about what the problem is saying, so once that problem is solved, I forget the next day. Any tips to improve this will be appreciated. Thank you. :)
  2. jcsd
  3. Feb 8, 2010 #2
    Hey, this is a funny little business, electromagnetism.

    I know in Electrostatics: the physical big picture stuff is total charge, superposition, and Coulomb's inverse-square-force-law. 'Course: it's more complicated than that for only one reason: geometry. You may understand electromagnetism inside and out, but it's doing those crazy "charged squuare loop" integrals that, I think, would trip most up.
  4. Feb 8, 2010 #3
    This is true... especially assuming you're in a calculus-based version of introductory physics.

    The math level required to enroll in our (semester-system) institution's engineering/science E&M is co-enrollment in Calculus II (single-variable integral calculus); however, since I teach the accelerated summer course at our institution, I strongly recommend that students have completed Calc II, rather than be co-enrolled. (As an undergraduate, I was also a term ahead in calculus versus physics, which i believe contributed to my physics success.)

    Sadly, at this level it's not so much physics understanding, as problem solving, and at least at our institution E&M is rather a weed-out course for engineering. Basically in that problem solving, if you can keep track of units and slightly analyze your result for reasonableness, you're ok.

    On my tests, I also try to also include an "easy" second part to problems that either REQUIRES analyzing the solution for reasonableness (such as taking a limit of the solution in some manner), or looking at a slightly different geometry (say putting a test charge inside the center sphere in a charged spherical capacitor rather than between the spheres to find the force on it)... parts that could earn the student's points based on understanding. Of course, I wasn't always so good at test design for this level...but I think many of the more-experienced instructors are... so you might want to see if the problems on your tests have some possibility for such insight.
  5. Feb 8, 2010 #4


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    Yeah indeed, the mathematical part of this course is a big part of it. It's very common to do a triple integral or a double one to calculate the charge of simple volumes/figures. This requires at least calculus 3 background. Maxwell's equations cannot be understood without calculus 3, in my opinion. I'm not sure what your introductory course consist of, but I guess it goes that far.
    And about the formulae used in Physics, some requires to be accepted as axioms. For instance Coulomb's law. You have to understand it well and take it as a truth. It comes from experiments.
    Then, if you had or are currently taking a calculus 3 course, you can understand what is the electric potential function and its properties, without memorizing as much as you can.
    What is also important is to know all of the basic formulae, i.e. the definitions. You have to know the definition of the capacitance for example. Memorize it. Then understand it. Force yourself, read several books to see what they have to say about the capacitance. After this, you'll be able to figure out yourself what is the capacitance of a varieties of capacitors, without memorizing a single formula, except the definition as I said. This is how I do and I'm going to take the final exam on Tuesday of this course.
    After solving an exercise, you shouldn't have the feeling you just plugged and chugged values into a formula. You always have to understand what you are doing, if it makes sense. Many times it won't make sense, you'll know you're wrong somewhere. Think again the problem and if you can't figure out what's wrong, ask for help to friends or here. If you're forgetting how you solved a yesterday's problem, it's likely because you did the "plug and chug" way. Maybe the problems aren't really challenging or made to make you understand. Do many different kind of problems, as much as you can. If you see a problem that seems so difficult that you don't know how to start, choose it! It's a very nice opportunity to understand and learn something new, trust me.
    And lastly, do not let a problem you don't understand unsolved. You'll have fills to gasp later, you can't escape at university and that's a good thing of it.
    Good luck.
  6. Feb 13, 2010 #5
    Thank you everyone, for your answers. :)
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