I need to learn electromagnetism ASAP

>>8850828
To expand, I can't comprehend flux. I know what field is and how do you derive it from integration, but I just don't understand flux, it's non-intuitive for me. Please help

>>8850828
IT freshman btw

>>8850838
I found Khan Academy to be very understandable, but they don't mention flux

>>8850828
>by Pearson
>listing the publisher and not the author

Are you retarded?

>>8850828

Just do the problems. You still haven't specified what your test is on, or if it's a final.

>>8850861
>Are you retarded?
That's what I mean by "brainlet"

It's Sears and Zemansky's University Physics

>>8850891
Thanks, that's probably what I'll do.

It's not a final, it's just a test on electromagnetism, it says it covers

> electrostatic field in vacuum and materials
> direct current
> magnetic field in vacuum and materials
> grand unified electromagnetism theory
> waves

For know I know the force for two charges formula, end electric field formula for one charge, and I can't do the proofs with integrals for rings, plates and other stuff manually but I understand them conceptually (I think).

So I'll go to Khan academy and learn Work formula and anything else I can't get from there.

I also need to know how to get the direction of induced magnetic field and that sort of stuff, but all the books provide the proofs I have no interest in, I just need the tools and practice.

>>8850828
read Griffith's
use these notes:
http://www.damtp.cam.ac.uk/user/tong/em/electro.pdf

I believe

>>8850926
Thanks!

>>8850828
Flux is [math] \int \mathbf{B}\cdot\d\mathbf{A} [/math]. That's literally it, it's no different than electric flux.

>>8850907
Here is a quick course on electromagnetism. In the vacuum we have:

[math] \mathbf{F} = q\mathbf{E} [/math] and [math] \mathbf{E} = \frac{q_1q_2}{4\pi\epsilon_0} [/math].

Electric fields obey superposition, so the field due to a collection of charges is the sum of the fields due to individual charges. This allows us to trivially find the electric field at a point [math] r [\math] due to a distribution of charge:

[math] \mathbf{E} = \frac{1}{4\pi\epsilon_0}\int\frac{\rho(r')}{|r - r'|^3}d^3r'[/math]

As an exercise try calculating the electric field along the axis of a ring of current with radius [math] R [/math] and current density [math] \lambda [/math]. In electrostatics, since the curl of the electric field is zero, we can define an electric potential so that [math] \mathbf{E} = -\nabla \phi [/math]. For highly symmetric charge distributions you can use Gauss's law in integral form, [math] \int\mathbf{E}\cdot d\mathbf{A} = \frac{Q_{enc}}{\epsilon_0} [/math]. See chapter 2 of Griffiths and work out the examples he does for various highly symmetric distributions.

For electric and magnetic fields in matter I recommend reading Griffiths, chapters 4 and 6.

For magnetic fields, see chapter 5 of Griffiths. it is pretty similar to electrostatics except with cross products, so you have to be more careful about the direction your fields are pointing. The key feature is that magnetic fields cannot do work by themselves.

For unified EM theory and waves, the key point is that the Maxwell equations involving curl can't satisfy divergence of curl = 0, so you need to add an extra corrective term (the displacement current). It is easy to work this out. Then, we observe that the fields obey a wave equation with wave velocity equal to the speed of light.

Seriously just read Griffiths.

>>8850970
Ok, I have a few typos in there but whatever. Just read Griffiths and make sure you can work the examples that he does, and use your big general physics book for the material on circuits that Griffiths decides not to cover and for practice problems.

>>8850984
Thank you, I will read Griffiths.

>>8850834
Flux is just the stuff going orthogonally to the field, rather than circulating inside it.

>>8850828
Pick up a copy of Classical Electrodynamics by Jackson at your school's library. If you aren't a brainlet you should be able to get through the first few chapters on electrostatics and magnetostatics in ~1 day.

>>8850834
Flux is the amount of "stuff" coming out of a region. If you have a charge in space, you can infer the total charge contained in a region by calculating the flux of the E field around the charge. If it is a point charge, then it is easiest to use a spherical shell as your imaginary surface. You then integrate the flux of the field along your imaginary surface. Essentially, adding up the values of the flux at each point along a surface can tell you something about what is inside of it.

Ma favorite part from Griffiths is the triangle of formulas for electricity and magnetism. Great for intuition behind going from density, to fields, to potentials.

Why didn't you recommend Khan academy? It's way simpler.