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Homework Help: Another question about magnetic fields

  1. Jul 24, 2008 #1
    1. The problem statement, all variables and given/known data

    Wut force will the rod that rests on the 2 parallell rails feel when the battery switch is closed

    a. to the right
    b. out of the page
    c. to the left
    d. into the page

    2. Relevant equations

    based on the principle of lenz's law

    3. The attempt at a solution
    i feel like b, to counter the into the page force , but I don't have really a great idea
  2. jcsd
  3. Jul 24, 2008 #2
    you're trying to find out the force on the rod. According to the right-hand rule, the force will be perpendicular to both the current and the magnetic field. Do you know which way the current is running? What is the direction of the field? Use the RHR.
  4. Jul 24, 2008 #3
    Then It will go to the right, away from the battery, correct?

    With the right hand rule, fingers are straight and thumb is pointing away from fingers at a 90* angle. A line going directly from thefinger tips will be the direction of the magnetic field. A line coming straight out of your palm will be the vector of the charge (or the direction of the current). And thumb will be pointing in the direction of the force applied on that charge by a magnetic field.
  5. Jul 24, 2008 #4
  6. Jul 24, 2008 #5
    is the answer correct?
  7. Jul 24, 2008 #6
    No it's not
  8. Jul 24, 2008 #7
    but by this I get the thumb to point out of page, the fingers to point to the right, and the force to point directly up...and I do not see up as a choice...aaah i cant conceptualize
  9. Jul 24, 2008 #8
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