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Homework Help: Magnetic fields

  1. Feb 26, 2007 #1
    1. The problem statement, all variables and given/known data

    An artery has an inside diameter of 3.20 mm and passes through a region where the magnetic field is 0.065 T.
    If the voltage difference between the electrodes is 155 µV, what is the speed of the blood?

    2. Relevant equations

    V=kq/r E=kq/r^2 v=E/B

    3. The attempt at a solution

    I know that I have to ultimately use the last equation to find out velocity, but I need to first find out E. I tried using the second equation, but I am not quite sure as to what I'm doing wrong. First of all, is that right equation? For q, am I supposed to use the charge of an electron/proton? is r supposed to be entire diameter or should I divide it half?
  2. jcsd
  3. Feb 26, 2007 #2
    Remember that V is a scalar and E is a vector. They are related somehow or another...
  4. Feb 26, 2007 #3
    There is a simple equation for induced emf that applies here
  5. Feb 26, 2007 #4
    In my calculations I wasn't able to include V, but I know that I should. However, I don't know how the two relate to each other in an equation....Also, I don't think that I've learned about emf...
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