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Homework Help: A few Electromagnetic questions

  1. Apr 8, 2007 #1
    A: 1. The problem statement, all variables and given/known data

    http://i12.photobucket.com/albums/a234/Xuxyz/battery.jpg" [Broken]

    (a) i. Using the information in the graph, determine the potential difference Vo across the resistor immediately after the switch is closed.

    2. Relevant equations
    Vo = Io * R

    3. The attempt at a solution
    I don't know how to find Io using the grap, because as you can see from my link, it doesn't intersect at a specific point.


    B: 1. The problem statement, all variables and given/known data

    http://i12.photobucket.com/albums/a234/Xuxyz/04-08-2007015444PM.jpg" [Broken]

    I only need help on part f

    2. Relevant equations

    I don't know.

    3. The attempt at a solution

    None, sorry. I don't have a clue.


    C: 1. The problem statement, all variables and given/known data

    http://i12.photobucket.com/albums/a234/Xuxyz/04-08-2007020007PM.jpg" [Broken]

    Only part D

    2. Relevant equations

    EMF = vBD
    I = vBD / R


    I know this is a lot, but I would appreciate any and all help.
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Apr 8, 2007 #2
    For number 1, it looks to me like the graph shows a current of about 9.5 A??

    *For your second question, what is happening as the loop is moving away from the wire?*
  4. Apr 8, 2007 #3
    It's actually slightly below 9.5 A

    The Magnetic field strength is decreasing.
  5. Apr 8, 2007 #4
    1. Okay, slightly less than 9.5 A. :rolleyes:
    2. So if the field strength is decreasing, what about the flux?
  6. Apr 8, 2007 #5
    But I need an actual number for the equation to work.

    The flux would be decreasing, too?
  7. Apr 8, 2007 #6
    1. You must use your eyeball.
    2. Yes, the flux is decreasing, good. From this, can you tell me which direction is the induced current.
  8. Apr 8, 2007 #7
    I don't need to know the direction of the current, I need to figure out what it's equal to.
  9. Apr 8, 2007 #8
    Well, I thought you might want to learn what is happening.
    What does a changing flux produce?
  10. Apr 8, 2007 #9
    The induced current is counterclockwise.
  11. Apr 8, 2007 #10
    Very good.
  12. Apr 8, 2007 #11
    But what about it's value?
  13. Apr 8, 2007 #12
    A changing flux induces an emf around the circuit. Find out the relationship between this emf and other physical quantities.
  14. Apr 8, 2007 #13
    EMF = the derivative of flux vs time.
  15. Apr 9, 2007 #14
    So can you quantify how the flux changes?
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