1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Over what frequency range are Maxwell's equations valid?

  1. May 2, 2016 #1
    1. The problem statement, all variables and given/known data
    I am studying for an Optics exam and in one of the practise tests is the following question: "Over what frequency range are Maxwell's equations valid?"

    2. Relevant equations
    Maxwell's Equations

    3. The attempt at a solution
    I've searched through my Griffiths Intro to electrodynamics, and all over Google, but came out short. Any leads would be appreciated.
     
  2. jcsd
  3. May 2, 2016 #2

    berkeman

    User Avatar

    Staff: Mentor

    Do you see any frequency dependent terms in Maxwell's Equations? Are you familiar with how to work with differential equations like the linked system of Maxwell's Equations?

    https://upload.wikimedia.org/wikipe...quations.svg/500px-Maxwell'sEquations.svg.png
    500px-Maxwell'sEquations.svg.png
     
  4. May 2, 2016 #3
    I should add that this is not homework for a class that I am taking, nor am I receiving any marks for answering this question.
    Yes I am familiar with solving DEs (I have a math degree). I am also familiar with Maxwells equations (I also have a physics degree). The question is literally as I have posted it - my best guess is that the these laws are not good at the quantum level and QED must be used (I am not too good at QED, I only took one course in subatomic physics).

    I should add that this is not a homework question for a course I am taking. Nor am I receiving any marks for answering this.
     
  5. May 2, 2016 #4

    berkeman

    User Avatar

    Staff: Mentor

    How are these two statements related? Your OP said nothing about QM, only about frequency limitations...
     
  6. May 2, 2016 #5
    It's just a guess - trying to come to an answer through discussion. Any constructive input is appreciated :)
     
  7. May 2, 2016 #6

    berkeman

    User Avatar

    Staff: Mentor

    I think you are over-thinking it.
    What level is this question anyway. From your OP it sounded like it was at a pretty basic level:
    Opticians don't do much with QM.

    OTOH, if this is for a Quantum Optics class, there may be a different answer, I suppose.
     
  8. May 2, 2016 #7
    Ah I should have specified the level. The exam is for an undergraduate optics at an advanced EM level (maybe 4th year physics).
     
  9. May 2, 2016 #8
    Even if I am overthinking it there are only two possibilities: either Maxwells equations are valid for all frequencies, or they are not. If not, what are the ranges and why?
     
  10. May 2, 2016 #9

    berkeman

    User Avatar

    Staff: Mentor

    So QED may be involved? i'm not familiar with any frequency limitations of Maxwell's Equations, but are they modified for QED? That's kind of a different question.
     
  11. May 2, 2016 #10
    I doubt QED is involved - that's too advanced for this course. Like I said it was just a guess - maybe not a good one! I cannot think of anything else besides that (trying to remember my subatomic physics course).
     
  12. May 2, 2016 #11

    berkeman

    User Avatar

    Staff: Mentor

    At least from my perspective, frequency limitations do not come into effect with the basic Maxwell Equations. Probably a trick question...
     
  13. May 2, 2016 #12
    Yes you might be right. Perhaps I was hoping there was more to it. I'll take it as it is for now unless someone else has any thoughts. Thanks for your input!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Over what frequency range are Maxwell's equations valid?
  1. Maxwell's Equation (Replies: 9)

  2. Maxwell's equations (Replies: 6)

  3. Maxwell's equations (Replies: 3)

Loading...