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B What moves in a magnetic field?

  1. Jul 10, 2017 #1
    So if you have a permanent magnet what is moving along the magnetic field lines? Electrons? Photons?
     
  2. jcsd
  3. Jul 10, 2017 #2

    Drakkith

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    Nothing is moving along the field lines. Field lines don't even exist. They just help us visualize the magnetic field around the magnet. They're like the latitude and longitude lines on a globe or the contour lines on a topographic map that represent elevation.
     
  4. Jul 10, 2017 #3
    I don't mean the field lines themselves. What is changing in the magnetized area?
     
  5. Jul 10, 2017 #4

    Drakkith

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    I'm sorry I don't understand your question. Can you elaborate a bit or give a specific example/setup?
     
  6. Jul 10, 2017 #5
    What on the atomic level is changing that causes magnets to pull?
     
  7. Jul 10, 2017 #6

    Drakkith

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    Nothing. It is an inherent property of the electromagnetic force. Just like how opposite electric charges attract. Now, that doesn't mean that a magnetic field can't cause changes to the atomic structure of matter, it just means that these changes aren't the direct cause of the attraction.
     
  8. Jul 10, 2017 #7
    Does a magnet attract faster than the speed of light?
     
  9. Jul 10, 2017 #8

    Drakkith

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    What does that mean? How is the speed of an attractive force measured?
     
  10. Jul 10, 2017 #9
    Okay so say a magnet was placed at a specific position A. Say 1 meter away is position B. Does the affect of the magnet or light reach position B faster.
     
  11. Jul 10, 2017 #10

    Nugatory

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    Both arrive at the same time because they are the same thing - light is electromagnetic radiation, which is to say a propagating change in the electromagnetic field.
     
  12. Jul 10, 2017 #11

    Drakkith

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    Well, remember that we can't just pop things into existence in real life, so the answer to questions like this may not always be meaningful. We'd have to move magnets into position from somewhere else or assemble them out of matter.

    However, let's say that we have a magnet at position A, and position B is located 1 meter away. By moving the magnet we would create a change in the field. This change would propagate at light speed from point A to point B.

    Does that help?
     
  13. Jul 10, 2017 #12
    So maybe I just have a problem with my understanding of the electromagnetic spectrum but how exactly does magnetism fall into that? Everything on the electromagnetic spectrum has a wavelength and I believe is photons but magnets do not?

    Also does everything with a magnetic force affect everything else the same way gravity does?

    and thanks for answering my questions
     
  14. Jul 10, 2017 #13

    Drakkith

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    The electromagnetic spectrum refers to the range of frequencies/wavelengths of electromagnetic radiation, which are waves in the electromagnetic field. A static magnetic field is not a wave and cannot be said to have a frequency or wavelength. It wouldn't fall on the spectrum at all.
     
  15. Jul 10, 2017 #14

    anorlunda

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    You are confusing us and yourself by using the words move and change in your question. Please try again. What are you really asking.

    Is your question, "What is the difference between magnetic and non-magnetic materials?"
     
  16. Jul 10, 2017 #15
    What is the difference between a magnetic field from a magnet and the electromagnetic field? How do they interact?
     
  17. Jul 10, 2017 #16

    Drakkith

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    The magnetic field is a manifestation of the electromagnetic field. Basically, it turns out that electric field and electric phenomena (such as the attraction of electrically charged particles) can be linked to magnetic field and magnetic phenomena (such as the attraction between magnets) in such a way as to suggest that they are actually the same thing just manifesting in a different way. For example, a moving electric charge produces a magnetic field in addition to the electric field is normally has. A moving magnet produces an electric field in addition to the magnetic field it usually has. Scientists ended up developing a handful of equations that can describe all electric and magnetic phenomena. These equations are called Maxwell's Equations and are extremely important. Everything from the circuit laws that govern computers and the wiring in your house to the behavior of plasma inside a fusion reactor can be derived from these equations.

    Because a handful of equations can describe all of these different electric and magnetic phenomena, scientists choose to label them all as being manifestations of a single force, the electromagnetic force. This also requires that we unify the magnetic and electric fields into a single electromagnetic field.
     
  18. Jul 10, 2017 #17
    Since magnetism is a non-contact force and electric field is a wave of particles of energy(photons) why are these considered the same thing? They seem to both behave very differently and their definitions seem very different.

    Doesn't electric field not put a force upon things while magnetism is defined as a force? It doesn't seem to be the electric field that causes the magnetic field but instead the moving of electrons in the wire.
     
  19. Jul 10, 2017 #18

    Drakkith

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    The electric field is not a wave of photons, it is a type of field (which has a specific definition in science), and I just explained why the electric and magnetic fields are considered different manifestations of the same thing. They are described by the same math and can both be easily "transformed" from one to the other just by moving a particle or magnet. The basic fact that transforming one to the other requires only relative motion means that we really never find one without the other. It's just that in a stationary situation we find that either the electric or magnetic components are zero.

    I don't know what you mean. Electrically charged particles feel forces. These forces can be electric, magnetic, or a combination of electric and magnetic forces. The fact that opposite charges attract each other through their electric fields is the fundamental reason why we have atoms and molecules. If they didn't, then the protons and electrons making up atoms would not bond to each other.

    You are correct. Neither the electric field nor the magnetic field cause the other. Moving charges are one source of magnetic fields, but even a stationary electron has a magnetic field, despite having no motion. The magnetic field of a permanent magnet also requires no movement of charges.
     
  20. Jul 10, 2017 #19
    Sorry I meant, Since magnetism is a non-contact force and electromagnetic field is a wave of particles of energy(photons) why are these considered the same thing? Just because they can be converted doesn't make them the same. That would be like saying kinetic and potential energy is the same thing since they can be converted and where you find one you can find the other or the other is 0.
     
  21. Jul 10, 2017 #20

    Drakkith

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    The EM field is not a wave of particles. It is a field. An EM wave is probably what you're thinking of, but that's a wave within the EM field. The field itself is not a wave.

    They are the same thing. Or rather they are manifestations of the same thing. Both kinetic energy and potential energy are forms of energy.
     
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