Electricity & Magnetism course difficulty?

[elementG]

ive been hearing about this course in the community college i attend and from what I've heard is that this is the hardest lower division physics course that most people take. I am a civil engineering major and the people I've talked to are also engineering majors. any advice for those who have yet to take it? for those who have taken it, how did you do? what got you through it? any advice appreciated, thanks!

 

[DavidWhitbeck]

I majored in physics and I also thought it was the hardest of the lower division physics courses.

My advice is to try to master vector calculus before (as opposed to concurrently) you take the class. The subject will appear to be abstract, and even if your intuition was as sharp as a tack in mechanics, it won't be in e&m. The best way to build your intuition is by extra problem solving.

Also make sure that you use a very helpful resource-- your TA and prof office hours. And if your school also has drop in tutoring available, use that as well.

 

[Dr Transport]

I majored in physics and I also thought it was the hardest of the lower division physics courses.

My advice is to try to master vector calculus before (as opposed to concurrently) you take the class. The subject will appear to be abstract, and even if your intuition was as sharp as a tack in mechanics, it won't be in e&m. The best way to build your intuition is by extra problem solving.

Also make sure that you use a very helpful resource-- your TA and prof office hours. And if your school also has drop in tutoring available, use that as well.

Integral Calculus is also a requirement to have beforehand...

 

[DavidWhitbeck]

Integral Calculus is also a requirement to have beforehand...

Good point, you do integrals far more often in that class than you do in mechanics. Of course it's nice when you can gaussian surface your way out of them but I suppose sometimes you can't. And then there are those de's for RC circuits and all that.

 

[symbolipoint]

Yes, difficult is E&M fundamental course, been long time ago --

This course uses somewhat more intricate Trigonometry, Vectors, and Calculus; all in fairly analytical ways, much more so than what you find in the fundamental Mechanics and the fundamental Modern Physics courses. Your Algebra skills need to be solid throughout most of the intermediate level also. Solving electricity flow problems will rely on Trigonometry and the idea of "potential". In mechanics, you can literally see almost everything you study; in E&M, you make measurements to determine things that you cannot see judge and calculate about things that you cannot see.

I'm also curious. Anyone repeated the fundamental E&M course and learned better, and also understood exactly how it is more difficult than Mechanics?

Also curious: Are there mechanical equivalents to Maxwells equations?

-like I said, it has been a very long time since I studied any Physics-

 

[dontdisturbmycircles]

Integral calculus is basically the main tool I used in my first E&M course. Just do the homework and you'll be fine. I got an A+ in the class..

The best advice I think one can give for any physics course is to do the homework by yourself without the aid of your notes. It is completely possible to hand in a homework assignment and get 100% on it without having any idea whatsoever what it is you just did. (i.e. looking for examples in text that match assigned homework etc).

In response to symbolipoint, E&M was 'harder' than mechanics in my point of view because it demanded more scientific intuition. Also in mechanics stuff other than gyroscopic forces are mainly common sense. Whereas its not common sense to believe that the electric field anywhere inside a hollow conducting sphere is 0. (Without the benefit of hindsight.) Even though I suppose that one could argue that it may seem plausible. But try telling me that ampere's law is common sense. :P

 

[symbolipoint]

Another thought comes up: the first course of Electricity and Magnetism is difficult because students have very little conditioning about fields and third-semester Calculus - they are too new for the students as well as less intuitive. What I mean by "little conditioning" is that students usually have not yet had enough exposure and experience with these ideas to have become skilled and comfortable with them.

 

[FrogPad]

Typically you will get a big curve in this class. The majority of the people aren't up to snuff on the math, and it shows during the tests.

Personally, I loved the introduction to vector calculus in this book:
Field and Wave Electromagnetics - Cheng [https://www.amazon.com/dp/0201128195/?tag=pfamazon01-20]

Understand the math and you will understand the class.

 

[FrogPad]

Another thought comes up: the first course of Electricity and Magnetism is difficult because students have very little conditioning about fields and third-semester Calculus - they are too new for the students as well as less intuitive. What I mean by "little conditioning" is that students usually have not yet had enough exposure and experience with these ideas to have become skilled and comfortable with them.

You know... the first EM physics (taught outside engineering) was just horrible for me. They would introduce concepts like the Gaussian surface and I had no idea what the hell they were talking about. They would present all this "complicated" (at the time) math and say things like... "here is Maxwell's equations... we really could just give you these, and this is the whole course."

bull ****... If that was the case, why did I have to memorize all these stupid derived algebraic expressions and apply them during the test. If I only needed Maxwell's equations, why didn't the Professor's test solutions start from Maxwell's equations and derive everything he needed?

The problem was, it was like he was trying to be like... "you guys have never seen math this crazy!" I remember thinking, how can one solve integrals like that? (I didn't really know of numerical methods at that point).

Anyways, I'm kind of going off on a tangent here. The problem with that class, is there is a ton of information to absorb and it really needs the math to be setup proper before it can be taught (in my mind) correctly. It is not fair to flash a bunch of vector calculus at students who have not had it, or are concurrently taking it.

I got a B in the physics E&M and an A+ in the engineering E&M... what was the difference? For the engineering E&M I knew the math...

 

[gravenewworld]

Yes. I absolutely HATE E&M with a passion. I was much better at QM than E&M. I wasn't bad at E&M, but you have to be an absolute master with vectors and vector operations to ace E&M.

 

[DavidWhitbeck]

I got a B in the physics E&M and an A+ in the engineering E&M... what was the difference? For the engineering E&M I knew the math...

It was the same with me except substitute engineering for upper division physics. I remember distinctly the problem that I had in that class was that I did not see the underlying relationships between the equations, and lacking that I didn't have any kind of coherent problem solving strategy. It looked to me like everything the prof had done were tricks, when really they were just methods and I was not understanding the underlying logic that tied it all together. I got it fine in the upper division class and the graduate level class though.

 

[Howers]

I actually found E&M easy compared to mechanics. I have only used Griffiths text though, and I've heard it isn't the most in depth.

Mechanics problem get really weird when you have work from scratch with just a graph or a diagram. And QM? How can you compare vector calc to PDE?

 

[Feldoh]

ive been hearing about this course in the community college i attend and from what I've heard is that this is the hardest lower division physics course that most people take. I am a civil engineering major and the people I've talked to are also engineering majors. any advice for those who have yet to take it? for those who have taken it, how did you do? what got you through it? any advice appreciated, thanks!

It is a fairly difficult class, both conceptually and mathematically... I still don't really get induction completely, nor have I mastered the vector calculus that is required (Gauss' Law is still horribly difficult in some cases). I think what it comes down to is time investment. If you put in the time it's quite do-able.

 

[Monocles]

Are you guys talking about what is typically Physics 2 or E&M classes beyond that (that usually only Physics majors take).

 

[DavidWhitbeck]

And QM? How can you compare vector calc to PDE?

Tell me about it. I remember my introductory QM class it would be like this--

Solve Schrödinger's Eqn for potential so and so...

Prof's solution: "Ansatz: exact solution. Hey look it works! q.e.d."

My introductory qm class was also where I first learned Fourier transforms, fun stuff.

 

[DavidWhitbeck]

Are you guys talking about what is typically Physics 2 or E&M classes beyond that (that usually only Physics majors take).

With the exception of maybe Howers we're all talking about the lower division class.

 

[mathwonk]

throw down a handful of filings in a magnetic field. see how they spread themselves out in a curling pattern of little line segments. obviously the right mathematics to describe this is vector fields.

the clear message of this thread is that E&M is hard if and only if you do not have the mathematics of vector fields down well ("div, grad, curl, and all that"). so take a hint.

 

[Feldoh]

Are you guys talking about what is typically Physics 2 or E&M classes beyond that (that usually only Physics majors take).

Typically the second class in the physics sequence is E&M for undergrads...

 

[elementG]

thanks very much for the insights guys. its very informing to hear your experiences with e&m. i see that the main advice is simply the mathematics involved. I am only in calcII and i'll be taking calcIII with mechanics. are vectors are in calcIII?

 

[mgiddy911]

I found lower div E&M not so bad, ie. second semester of basic physics course.
However, My upper div E&M course was torture, such that I decided if I did not get an adequate grade I would drop my physics major and become a math major.

I took Calc 3 my first semester and thus had it when taking lower div E&M, i'd say it helped a little, atleast I feel I had an advantage over the other students

 

[lisab]

Lower division E&M was nothing compared to upper division E&M. The upper division kicked my butt!

I found QM to be very enjoyable, almost - dare I say? - easy. It seemed that those students who took to Dirac notation easily had no problems, but those who struggled with the new notation had a heck of a time.

 

[DavidWhitbeck]

Lower division E&M was nothing compared to upper division E&M. The upper division kicked my butt!

What did you use for upper e&m? We used Purcell in my lower level class and I thought it was harder than Griffiths which is what we used in the upper level class. Griffiths is a very easy book. Easy to read, easy exercises. And to spend an entire year on it is sweet. I would understand if you had a semester course, it might feel difficult to do it all in that time span.

Were you at one of those schools like MIT that used Jackson?

 

[PhilosophyofPhysics]

E&M has definitely been the toughest undergrad course I've had. I only have QM left.

I think it required a lot more studying and working out of problems than I put into it, more so than any class I've had so far. Anyway, it wasn't one of my favorite courses, though I can see how it would be lovely if I actually was better at it.

 

[lisab]

What did you use for upper e&m? We used Purcell in my lower level class and I thought it was harder than Griffiths which is what we used in the upper level class. Griffiths is a very easy book. Easy to read, easy exercises. And to spend an entire year on it is sweet. I would understand if you had a semester course, it might feel difficult to do it all in that time span.

Were you at one of those schools like MIT that used Jackson?

D'OH! I was at the University of Washington - we used Griffiths. My real problem was with my calc class. We used a book that didn't have multivariate chapters. The instructor (I took it at a community college) supplimented with various materials, but it was just sort of disorganized. I just didn't have the "div grad curl" stuff down enough to really get the physics - I was too tied up with the math.