Learning curve of Electromagnetism?

[martinlematre]

I'm taking a first year physics course and have been having a little trouble with the basics of Newtons laws and forces and whatnot, though nothing that can't be fixed with a bit more hard work.

I'm looking ahead now and seeing a lot of EM material, and after kind of taking a brief look at the homework, contents and whatnot I must say it seems quite unfamiliar.

Do you find first year EM with no calculus to be a lot harder than the rest of first year content? I am just wondering if I'm going to have some trouble with it.

 

[thegreenlaser]

My intro to EM class was quite difficult, but what made it hard in my opinion was the calculus. It was the first time we really used calculus to solve problems outside of a math class, so we were learning new physics as well as using math we weren't very comfortable with. However, I did find it much more enjoyable than the non-calculus intro to EM I got in high-school, so I didn't mind taking the time and effort to really learn it. I found non-calculus EM to be hard just because I didn't enjoy it, but hopefully your experience will be different. If you've never seen EM before, the concepts can seem really weird and exotic, but usually what makes it so difficult is the inclusion of heavy math on top of foreign concepts, so you might not have a bad go of it if there's no calculus.

 

[vanhees71]

It's no accident that Newton discovered calculus when solving physics problems. It's the natural language of physics. Non-calculus physics is incomprehensible, at least for me. Of course, it's a bit work to learn all the stuff about the differential operators grad, div, curl, the Laplacian, and the integral laws and how to apply them, but it's really worth the effort, because then one has a great tool to solve all kinds of physics problems.

Another problem with electromagnetics is that it is still mostly presented in a quite old-fashioned way, as if it were easier to understand first the pre-relativistic way of presenting the material. In reality it's much easier to think about the electromagnetic field as a relativistic field what it in fact really is. Then a lot of trouble is avoided before you become aware of it, particularly all the quibbles about Faraday's Law, unipolar generators, etc.

 

[martinlematre]

Yeah I am not doing calculus intro.

 

[raopeng]

I agree with Vanhees71. Some intro calculus would greatly reduce the difficulties of EM. Although here they start the course in the same way from static fields with experiments to electromagnetic effects in which relativity might take a very some portion, some circuits, and Maxwell's Equations. I think this is in part because for first year students it is very difficult to grasp all the necessary mathematical formalism to start from relativistic point of view, notwithstanding more direct and with more insight, and it would be too abstract for some students. But if you are genuinely interested in EM, I feel trying to learn those mathematics on yourself won't be bad if the textbook you choose teaches this in close relation to physics.

 

[vanhees71]

The e+m theory lecture, I have in mind is for sure not for first-year students. Why should there be any theoretical e+m in the first year anyway? The theory course should start with some math as the physicist needs it urgently already in the beginning with is linear algebra, calculus up to simple differential equations and then classical non-relativistic mechanics+introductory relativistic mechanics. In the 2nd year you have e+m, and this of course can not start with relativsitic e+m already in the very beginning (although that's a pity, but that's how it is, except you do quantum mechanics first, and only then e+m, so that the students have heard some more theoretical physics before starting e+m, but on the other hand that makes it also inconsistent, because you need at least some basic e+m to start with real applications in atomic physics in the quantum theory lecture). An e+m lecture still can start with electrostatic and magnetostatic; then you go to Maxwell equations in the differential form (in the 3D formalism). That's fine, because this is already relativistically correct. Only when it comes to the "electromagnetism of moving bodies" you must use explicitly relativistic electromagnetics. Otherwise you have big mess and get an outdated picture, at best on the level of H. Hertz's electrodynamics in the late 19th century, but this causes more misunderstanding than comprehension what's really going on. The includes even practical issues as the homopolar generator!

 

[raopeng]

Eh I suppose here the schedule is not quite the same as in US because EM with all the topics listed above is indeed a first year course, much like in UK I hear. And indeed this causes all kinds of confusion like the homopolar disk and I only got to get a grip at it when learning the more advanced electrodynamics. So now I have the feeling that I would focus mainly on mathematical formalism first and some basic static field introductions, saving the more theoretical part for later, should I arrange it for myself. Those horrible explanations about electromagneticism only serves to confound the physics picture.