I wanna learn EM theory

[danzibr]

First, I did not really know what EM theory. I’m a total Physics noob.

With that said, any direction that starts with the absolute basics? I did some googling but got overwhelmed.

[Gray Mage]

At what level would you like to learn? And what is your background in math? A lot of EM theory relies on vectorial math.

[gomipile]

If you have at least a high school education in mathematics, I'd recommend Ramamurti Shankar's online video lectures for his Yale physics course:

https://oyc.yale.edu/physics/phys-200
https://oyc.yale.edu/physics/phys-201

These are designed to be taught at the same time as you are learning calculus in parallel.

[jayem]

At what level would you like to learn? And what is your background in math? A lot of EM theory relies on vectorial math.
To repeat the point it's something you pretty much do each year, and each time the last years course turns out to be a special case of the formula in the first lecture.

Broadly I'd say that you get
Electrostatics and Magnetostatics (qualitative, are you happy with drawing iron filings around a magnet?)
Electrostatics (quantitive) & Electric circuits (do you think you could work out orbits of electrons going round an atom? Bonus points if you can't for the right reasons)
Electro-Magnetic interactions (qualitative, are you happy in hand wavy terms describing a motor? a generator?)
Individual Laws of electromagnetism (Ampere's law, etc...)
Maxwells Laws (at this point you need to be able to hand Vectors in the abstract)
Going backward from Special Relativity, dealing with complex materials, etc...

[danzibr]

At what level would you like to learn? And what is your background in math? A lot of EM theory relies on vectorial math.
PhD in Geometry. Taught up to Calc 3.

Never did engineering or physics though.

If you have at least a high school education in mathematics, I'd recommend Ramamurti Shankar's online video lectures for his Yale physics course:

https://oyc.yale.edu/physics/phys-200
https://oyc.yale.edu/physics/phys-201

These are designed to be taught at the same time as you are learning calculus in parallel.
Thanks!

To repeat the point it's something you pretty much do each year, and each time the last years course turns out to be a special case of the formula in the first lecture.

Broadly I'd say that you get
Electrostatics and Magnetostatics (qualitative, are you happy with drawing iron filings around a magnet?)
Electrostatics (quantitive) & Electric circuits (do you think you could work out orbits of electrons going round an atom? Bonus points if you can't for the right reasons)
Electro-Magnetic interactions (qualitative, are you happy in hand wavy terms describing a motor? a generator?)
Individual Laws of electromagnetism (Ampere's law, etc...)
Maxwells Laws (at this point you need to be able to hand Vectors in the abstract)
Going backward from Special Relativity, dealing with complex materials, etc...
Interesting.

[gomipile]

Then yes, I'd recommend the Shankar videos, definitely. There are books to go with then now, too. They're not necessary and are basically just a polished and printed version of the lectures. But if reading helps you study and learn, as it does for me, they're worthwhile.

I learned all this stuff back in the 90s and early 2000s with books that were good, but a bit less elegant and streamlined.


Technically, if you just want to jump into E&M, you could handle a book like Purcell's Electricity and Magnetism, but I'd still recommend starting with an intro course like the Shankar videos to get the big picture first. Some universities do use Purcell for their freshman/sophomore honors course after an honors course in introductory mechanics(usually taught with the book by Kleppner and Kolenkow.) You miss out on a lot of the the interesting fluff, history, and connections that a general physics I and II course gives that way, though. That fluff isn't strictly necessary for the computational and strict understanding of these topics, but I think it helps build intuition.

Honestly, I'd recommend you work through the free homework exercises provided at the two links I pasted above as you watch the lectures at your own pace. Go through all of those I and II lectures doing as much of the exercises as hold your interest.

If you like Shankar's level of difficulty working with E&M, you might like the treatment in a book like Purcell after that. If you really want to keep going past that, Griffiths' text is at a somewhat higher undergraduate level again. "Finally," Jackson's text is at the introductory Master's level after that. At that point you'd have probably put several years just into learning this, but you'd be well prepared to read and work through journal papers in E&M.

Of course, you might end up studying a general book list of all the topics taught in undergraduate physics instead. /shrug. Your path is up to you. If you study at least a bit of the other pillars of classical and modern physics, you'll have a better understanding of applications and the range of applicability of the field you focus on, though.

I highly recommend www.physicsforums.com for help if you run into any conceptual difficulties. They place an emphasis on helping you work through problems yourself instead of handing out answers. Keep that in mind. They're really not trying to be rude if they go all "Socratic method" on you and ask what you've done already and ask pointed questions instead of answering your questions directly. They also have subforums devoted specifically to that type of help with textbook exercises/homework problems.

[Rockphed]

Everything in electromagnetics is a solution to a set of coupled vector differential equations. We commonly call these "Maxwell's equations", though he never wrote them in the form we know. Alternatively, you can write them as a set of integral equations, though without a better understanding of vector calculus than I have been able to keep down, going from the integral equations to the differential equations is non-obvious.

In my engineering classes, we had 2 different approaches to this over-arching theme of Maxwell's equations. On the one hand, we would impose a boundary condition on Maxwell's Equations and then try to find solutions that fit the boundary conditions and driving functions. On the other hand, we would analyze complex systems with fourier methods.

[Cicciograna]

If you want an interesting and pleasant book to read, I strongly suggest the Griffiths (https://www.amazon.com/Introduction-Electrodynamics-David-J-Griffiths/dp/1108420419).