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Faraday's Law

  1. Apr 9, 2007 #1
    1. The problem statement, all variables and given/known data
    An eager student cycles to college at 12 m/s. The metal handle bars are 60 cm wide and cut through the vertical component of the Earth’s magnetic field that has a flux density of 50 *10^(-6) T. Calculate the e.m.f induced across the handlebars. Explain why no current would flow through the student when he touched the metal parts of the handlebars even if he were a good electrical conductor.



    3. The attempt at a solution
    i can find the e.m.f:

    e.m.f= -3.6 * 10^(-4)

    but i can't explain why ...i think it has something to do with F=BIL


    any help would be much appreciated
     
  2. jcsd
  3. Apr 9, 2007 #2

    Dick

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    It is indeed because there is no changing flux through the loop of student+handlebars. But you can also ask yourself what e.m.f. is induced across the hands of the student.
     
  4. Apr 9, 2007 #3
    the emf that i calculated in the first part of the question?
     
  5. Apr 9, 2007 #4

    Dick

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    Yes, the student has the same e.m.f. as the handlebars. Does any current flow?
     
  6. Apr 9, 2007 #5
    i don't get it, i don't see how any of this is linked
     
  7. Apr 9, 2007 #6

    Dick

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    If you have two batteries with equal voltage and you connect their positive terminals together and the negative terminals together, how much current flows in the loop? It's the same problem.
     
  8. Apr 9, 2007 #7
    is it zero current?
     
  9. Apr 9, 2007 #8

    Dick

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    Yes. There's no e.m.f. difference between the two positive terminals or the two negative terminals. Do you see why your problem is the same?
     
  10. Apr 9, 2007 #9
    it's because the student and the handle bars have the same e.m.f....?
     
  11. Apr 9, 2007 #10

    Dick

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    Yes again.
     
  12. Apr 9, 2007 #11
    Oh thanx alot i get it all now
     
    Last edited: Apr 9, 2007
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