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Understanding magnetism

  1. Sep 1, 2008 #1
    I have few questions about magnetism:

    Is the current in permanent magnets the result of electrons orbiting the magnets atoms? Do electrons have to be in specific orbitals to create magnetism? Can the magnetism created by an electron's spin be understood through special relativity (lorentz contraction)? Do the electrons orbit around in the same way a current flows around in a solenoid? I have a feeling the answers to the previous questions are no bc they are dealing with quantum and not classical phenomenon.

    Does the magnetic field around current flowing through a straight wire have a north/south pole? If so, how, and does it depend on the direction of the current wrt another wire? Is the direction of the current in a wire the only thing that determines the magnetic pole? Do the north/south poles only arise from the sum of individual magnetic fields (like in a solenoid)? Will a compass needle point toward a wire with a current flowing through it, if so, does the alignment of the needle depend on the direction of current? Is the current in the wire inducing a current in the needle/ why does the needle change directions?

    When a magnetic field is shown on paper, do the x's and dots in circles represent the field lines themselves coming into/ out of the paper or the poles of the magnet? Why, or perhaps how, is the magnetic field represented as x's and dots if it is curving around the magnet? How does this visualizing system work?

    How does magnetic induction work? Can be induction be understood by special relativity, as is the magnetic attraction between two wires w/ current in same direction?

    Why do charged particles spiral around specific field lines instead of falling into the magnet? Can charged particles cross field lines or are they stuck on one line? Are there specific field lines corresponding to the energies of charged particles (like energy states for electrons)? Do the field lines exist at discrete levels?

    Why is the force on the charged particle always perpendicular to its velocity and why does that force act that way (why does the magnet push the particle away when it approaches and doesn't act like the mutual attraction between the two wires)? Does the polarity of the charged particle affect how it interacts with the magnetic field?

    How do charged particles stay in the radiation belts if the field lines terminate at the poles? Do they all end up as auroras? Do they jump back down to the bottom or go through the Earth somehow? Do the radiation belts themselves serve any beneficial purpose to the Earth? Can they be used as an energy source or for scientific experimentation?

    Is the current of the Earth's outer core that generates the magnetic field moving around like current in a solenoid? Is the current circling west to east?

    I apologize for asking redundant questions that would be covered in physics textbooks or classes. Unfortunately, I am unable to utilize those resources at this time. I also am having trouble searching and browsing the PF library. Thank you for your patience and help.
  2. jcsd
  3. Sep 1, 2008 #2
    flux lines can be thought of as having a tension along their length and a tendency to repel one another (they tend to spread out). electric field lines move directly into the charge while magnetic field lines form a circle around the particle. thats completely different and results in a completely different behavior. that is why the force is perpendicular to the motion of the particle
  4. Sep 1, 2008 #3
    the electrons arent moving in the permanent magnet. spin is simply a property of the electrons themselves.

    no north or south pole exists around a wire.

    leave relativity out of it until you understand the classical explanation.

    if you understand how an electron moving in a magnetic field experiences a force then you should understand induction.
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