Hardest content to learn for AP Physics C: Electricity & Magnetism

[cellist542]

What are some of the hardest concepts to learn in AP E&M? I am going to prepare for the exam with my previous physics teacher. I am currently a senior enrolled in AP Calc BC, and I already took AP Mechanics.

 

[berkeman]

What are some of the hardest concepts to learn in AP E&M? I am going to prepare for the exam with my previous physics teacher. I am currently a senior enrolled in AP Calc BC, and I already took AP Mechanics.

So this is calculus-based Advanced Placement E&M at the advanced high school level? Do you have a syllabus of the course that you could post? I can think of some at the lower-division university level, but I'm not sure they are appropriate for an AP high school course...

 

[vela]

There are a couple of different possibilities.

With E&M, you tend to lose the intuition you could rely on with mechanics. You probably have a good feeling for what 10 meters is, but what is exactly is 10 V? Resistance kind of makes sense, but what are capacitance and inductance?

Mathematics. (1) Vectors will make their appearance again. (2) Not only do vectors appear but the concept of vector fields does as well. (3) Applying the ideas of vector calculus to problems throws many students. (4) RC, RL, and RLC circuits are described by differential equations, which some find confusing. For many students, they're essentially learning physics and the necessary mathematics concurrently.

Recognizing and taking advantages of symmetry seems to be a problem for some students. The problems are much simpler if you use symmetry, but you can't do that unless you see it's there.

Seeing the big picture. It's easy to get lost in a zoo of formulas in intro E&M. If you see how everything is related, though, it can bring order to the apparent chaos. A lot of students, however, aren't terribly interested in learning where a formula comes from.

Magnetism is inherently three-dimensional because it involves cross products. Some people struggle with visualizing situations in three dimensions.

 

[cellist542]

So this is calculus-based Advanced Placement E&M at the advanced high school level? Do you have a syllabus of the course that you could post? I can think of some at the lower-division university level, but I'm not sure they are appropriate for an AP high school course...

It is a calculus-based course, and I have taken AP Calc AB.

The course has five units:

• electrostatics
• conductors, capacitors, dielectrics
• electric circuits
• magnetic fields
• electromagnetism

This is the official course description pdf. Page 18 is a little more specific as to what each unit includes.

 

[paralleltransport]

I think E&M is the first course in physics in high school one has to think seriously in 3-dimensional space with vectors. This is the main barrier which cause confusions. Before that, most students are used to be able to "draw" the solution on a 2-d plane (in fact, most high school mechanics problems are 1-d). But AP physics C E&M one has to get used to do symmetry arguments, right hand rules etc... These things are actually very much closer to how physics is done at an undergraduate level.