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Can the light create electromagnetic field?

  1. May 19, 2007 #1
    I will be very happy if you answer me. I tried several times on google to search about this but I didn't find anything. So please answer me, if you know the answer. Thank you.
     
  2. jcsd
  3. May 19, 2007 #2

    Danger

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    Light is an electromagnetic field. It is simply our way of identifying the visible (and near-visible) segment of the EM spectrum. There are several arbitrarily defined segments such as microwave, radio, X-ray, gamma, IR, etc.. Light is generally considered to be the part that we can see.
     
  4. May 19, 2007 #3
    Is it field?
     
  5. May 19, 2007 #4

    Danger

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    This isn't my area, so I can't give you a definitive answer. Essentially, though, yes; it is an electomagnetic field propogated by photons. If I understand it correctly, it is in fact 2 fields. One is electric, the other magnetic, and they travel together but oscillating at 90 degrees to each other. Someone more knowledgeable really has to take over from here.
     
  6. May 19, 2007 #5
    Yes. There is one and only one difference between, say, and EM wave at microwave frequencies and that of a red beam of light is the frequency of the waves. They are exactly the same in physical properties and makeup.

    Pete
     
  7. May 20, 2007 #6

    DaveC426913

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    Well.... two.



    One of them does a lovely job on my bag of Orville Redenbacher's..
     
  8. May 20, 2007 #7

    Danger

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    If the last commercials that I saw were any indictation, the microwaves had far more effect upon Orville's bag than just popping his kernals.
     
  9. May 20, 2007 #8
    If you say that the light is field, then I will make electromagnetic induction with light and get current in closed circular loop.
     
    Last edited: May 20, 2007
  10. May 20, 2007 #9

    ZapperZ

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    And you do! People who work in designing accelerator cavities have to deal with wall currents due to the the changing B fields. That is why you have lossy material.

    Zz.
     
  11. May 20, 2007 #10
    Can you give me some link or picture?
    So let's conclude the light is electric and magnetic field, right?
     
  12. May 20, 2007 #11

    ZapperZ

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    As I have mentioned earlier, please READ and STUDY the Hyperphysics link I gave earlier, especially on electromagnetism. You would not have to "conclude" such a thing if you had spent time doing that.

    Zz.
     
  13. May 20, 2007 #12
    Due to the high frequency of a light wave the light would not be able to penetrate inside a conductor. Same thing with x-rays.

    You wanted a picture, right? Draw a picture of an EM wave and you have by neccesity drawn a picture of light.

    What part of "Light is an EM wave" don't you understand?? Its a pretty simple idea.

    Pete
     
  14. May 20, 2007 #13
    Look man, if you say that the light is both part of magnetic and electric field, then, the photons "are moving" (so the magnetic field is moving), so it will produce current inside the conductor, right?
     
  15. May 20, 2007 #14
    It does produce a current. YES. Light does produce an electric current in any conductor it hits. Indeed.

    But light has a very high frequency. So because the frequency is so high, the "electrons in the conductor can't move fast enough". So the current is very very very very small.

    That's an oversimplification, but I don't know what else to say that will be understood.
     
  16. May 20, 2007 #15
    Why the electrons can't move so fast when the magnetic field of the light is moving so fast? Practically, when you move magnetic field faster, so the electrons in the conductor are moving faster, so the current is stronger.
     
  17. May 20, 2007 #16

    ZapperZ

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    1. The electrons are in a conductor, i.e. a medium. There are other things in their way!

    2. Electrons have MASS. EM field does not.

    Zz.
     
  18. May 20, 2007 #17
    Suppose you are pushing a child in a swing. Let's say you give a push every two seconds, to increase its amplitude. What would happen if you gave a push every tenth of second? The swing wouldn't move much. Make the experiment.
     
  19. May 20, 2007 #18
    I think you have wrong understood it. Look, I made that experiment. So if I push with 0.1sec (with same power) when I will get to 2 sec (0.1*20) so the swing's moving speed will be so fast, 20 times more then once in 2 seconds.
     
  20. May 20, 2007 #19
    It's hard to explain in such simple language. Pick up a spring. Hold it by one end. Move it up and down slowly. Now try moving it faster, and faster, and faster. Eventually the spring won't bounce very much anymore because you're shaking it too fast. It can't keep up.

    Electrons have mass, and they also have other things "holding" them. They are stuck in a "soup" of other electrons, so they can't just move as fast as you want.
     
  21. May 20, 2007 #20
    But man, when you practically moving magnet among conductor, it will induce current inside of the conductor. When you move the magnet very fast so the electrons are moving very fast, right?
     
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