Interpreting light as Maxwell's EM wave

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
65 replies · 7K views
vanhees71 said:
It's true for plane-wave modes

Well, I'm implicitly in the high-school mode, so I can't say anything about general case since I don't remember much about that (I took upper level classical electrodynamics course in 2012...).
 
Reply
  • Informative
  • Skeptical
Likes   Reactions: Rev. Cheeseman and BvU
Physics news on Phys.org
wonderingchicken said:
But the electric field and magnetic field for each point in space doesn’t have to be necessarily perpendicular, correct? For example, like in this picture the electric field and magnetic field is not perpendicular http://physics.thick.jp/Experimental_Physics/Section1/figures/fig1-4-2_en.png
They are perpendicular.

Your question has already been answered. In the far field (aka a EM wave) they are perpendicular. In the near field they do not need to be perpendicular.

Why are you still re-asking this question more than 20 posts later?
 
Last edited:
Reply
  • Like
  • Skeptical
Likes   Reactions: Rev. Cheeseman, berkeman and vanhees71
Ibix said:
A "skeptical" response from @wonderingchicken, so I will repeat a question I asked in #50: you have posted a lot of diagrams of electric fields that look like this:
View attachment 325468
Do you think that they are meant to imply anything about the electric field anywhere except exactly on the zero-width black line?
The axis is imaginary, correct? We can put the axis anywhere whether on top of the field, below, etc.

I have my own opinions regarding the electric and magnetic fields but this is not the "right" place to say anything about it because this entire forum is almost like a cult. Sorry for the honesty. o_O
 
Reply
  • Sad
Likes   Reactions: Dale and weirdoguy
wonderingchicken said:
The axis is imaginary, correct? We can put the axis anywhere whether on top of the field, below, etc.
This shows a pretty big misunderstanding of the whole concept here, as well as a misunderstanding of the question asked. I am going to repeat my original recommendation that you get a computer algebra software package, write a known solution, and try plotting it. That exercise will be more beneficial for you than another 20 posts asking the same questions again.

wonderingchicken said:
this entire forum is almost like a cult. Sorry for the honesty.
Sorry for the thread ban, honesty is not a good justification for insults.

@ other participants, you may respond further if you wish but be aware that the OP will be unable to reply here
 
Reply
  • Skeptical
  • Like
Likes   Reactions: Ibix and Rev. Cheeseman
wonderingchicken said:
I have my own opinions regarding the electric and magnetic fields

Opinions based on what? Lack of knowledge? You have shown in this and other threads that you are not here to learn. You just waste our time.

Dale said:
@ other participants, you may respond further if you wish but be aware that the OP will be unable to reply here

So is there any point in keeping this thread open? @wonderingchicken reply will be with "skeptical", as usual...
 
Reply
  • Like
  • Skeptical
Likes   Reactions: Dale, vanhees71 and Rev. Cheeseman
wonderingchicken said:
The axis is imaginary, correct? We can put the axis anywhere whether on top of the field, below, etc.
The axis is the thing in the diagram with the strongest claim to being real. The red line is a visualisation of the values of the electric field on that axis and only on that axis, nowhere else. It is no more real than a graph of economic growth - do you think a graph of a rising share price means that there's actually a set of hydraulic jacks somewhere lifting the price up off the ground?

The black line at least has the virtue of representing a set of points in a straight line by a set of (near) points in a straight line.
wonderingchicken said:
this entire forum is almost like a cult
If I stand on Earth and drop a ball then it will fall. Would you agree? Would anybody disagree? Are we all part of a cult of gravity, then? Or are we just dealing with reality?

We are trying to describe a shared understanding of a well-studied phenomenon in this thread, an understanding that we routinely use to design and build devices like the one you are reading this on. Dismissing it as a "cult" is just as daft as dismissing gravity as a cult. It just takes a bit more work to understand what we're describing because the details are not in your every day experience.
 
Reply
  • Like
  • Skeptical
Likes   Reactions: Dale, Rev. Cheeseman and vanhees71