# Too green for modern physics?

1. Aug 28, 2014

### bmrick

So my options for upper divisions this semester were pretty limited. I'm a physics major and the only upper divisions I've taken are intro thermal physics and math models. So this semester I ended up with electromagnetic theory one and modern physics. The first day of modern physics I was pretty lost. I'm not familiar at all who the wave nature of light, let alone with the wave nature of matter. Should I drop the class and finish e and m first or should I ride out modern physics? I'm not so much concerned about the grade as I am concerned that educationally d be better served doing some private study in e and m or general relativity or something

2. Aug 28, 2014

### JLR

Why not just stick with modern physics and do some "private study" in modern physics?

3. Aug 28, 2014

### bmrick

Because on day one my teacher was talking about the wave equation which I'm not at all familiar with. He said the course is more geared towards a pre quantum study than it is towards a historical account of modern physics. I'm worried that I'm going to be bogged down in mathematics that I don't understand because I don't have any preliminary education in the mathematics or theories that lead to modern physics. I don't want to just pass the class I want to understand what going on

4. Aug 28, 2014

### JLR

If you don't have the required math under your belt then how were you allowed to enroll in it to begin with? Prereq's should have prevented you from enrolling to begin with. The mathematics in modern physics isn't that bad really. You have to get used to using complex numbers a bit, but nothing you shouldn't be able to handle. There is a lot to take in conceptually though... very dense. If you have all your calc's under your belt and D.E. you should do fine with some supplemental reading as needed. Even if you have your math down you should still expect to have your head buried in the book due to the amount of info you have to take in. Is this reason to drop the course though? It isn't going to change anytime soon. If you do drop the course though out of survival in a school sense then spend time studying on your own so it isn't such a shock come next semester or whenever you take it again. Other than that the ball is in your court.

5. Aug 28, 2014

### bmrick

I need some work on differential equations but I can handle that. I was just worried that the course expected me to already understand a lot about waves and the wave nature of matter. No there aren't any prerequisites, but I found out today that the statistical mechanics course I've been allowed to enroll in, a 400 level course, is going to end up developing on quantum mechanics at some point. My advisor said it would be fine, the course teacher, however, was rather concerned. So I don't trust my schools recommendations for prerequisites, which is why I've turned to this community.

Could you perhaps explain to me a bit what modern physics is about? Wiki says it's the physics derived from considering matter and energy to be the same v thing. My professor said that the class is less about modern physics and more about preparing one for quantum, so there's that.

6. Aug 28, 2014

### JLR

"There is no education like self education."

7. Aug 28, 2014

### bmrick

Alright thanks JLR, I think for now I'm just gonna ride it out. If before the drop date I find myself memorizing math instead of learning math\ physics because it's too advanced, then I'll drop.

8. Aug 28, 2014

### Staff: Mentor

What textbook are you using in your Modern Physics course? Also, you presumably have had the standard two-semester intro physics course which covers mechanics, E&M, etc. Which book did you use for that?

A second-year intro modern physics course is often the place where students get introduced to wave equations of the form $\psi = A \cos (kx - \omega t)$ (real) and $\psi = A e^{i(kx - \omega t)}$ (complex), and it's often the first physics course where they have to use complex numbers. I covered that stuff in the intro modern course that I taught for many years. If that's what you're dealing with, then you'll just have to buckle down and get comfortable with them. It's common for physics courses to introduce new math that they need. My intro modern course was also where many students had to use partial derivatives for the first time, and I spent some time specifically on that.

Some schools have a separate "waves" course. You might check and see if you have one of those at your school.