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Why not a Left Hand Rule?

  1. May 5, 2004 #1
    All of the books and experience I can find offer only a Right Hand Rule for magnetism (current in a wire, particles). Since this is good for only positive particles, students must remember to switch the direction of the force when using the rule. Why not just use the left hand for negative and the right for positive? Am I missing something? It seems the easier and more logical way to go.
  2. jcsd
  3. May 5, 2004 #2
    Well flemming stole the left hand rule for showing the force on a current carrying conductor in a magnetic field. I presume it would just be confusing if there was an alternative for each one.
  4. May 5, 2004 #3
    I would think that with a negative partical, the vector is pointing in the opposite direction, so you really still need to apply the right hand rule.
  5. May 5, 2004 #4
    If the field and the velocity are the same the only difference is in the direction that your thumb is pointing (force). For students new to physics, is it more confusing to suggest they remember to switch the direction of the force in their minds as opposed to using their left hand? ....Fleming aside...
  6. May 5, 2004 #5


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    The right hand rule is just a convention. As TheDude said, you always apply the right hand rule, even for negative particles. We could just as easily have decided to use a left-hand rule, and everything would work just the same -- theories would still make the same predictions. All that matters is that you are consistent with the convention.

    The presence of such a choice is actually a rather deep characteristc of our physical universe. It turns out that the concepts of a vector and a dual vector are different in spaces of all dimension except three; the cross-product and its freedom for a convention can only exist in three dimensions.

    - Warren
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