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Homework Help: Archived Electrical energy dissipated in resistance of a wire

  1. Feb 18, 2008 #1
    1. The problem statement, all variables and given/known data

    A piece of copper wire is formed into a single circular loop of radius 10 cm. A magnetic field is oriented parallel to the normal to the loop, and it increases from 0 to 0.70 T in a time of 0.45 s. The wire has a resistance per unit length of 3.3 10-2 /m. What is the average electrical energy dissipated in the resistance of the wire.

    2. Relevant equations

    Emf = -NAB/t
    P = V(^2)/R
    E = Pt

    3. The attempt at a solution

    I used The first equation to find emf... -.0489V
    with that I plugged it into the second equation (for R I took my resistance per unit length times the circumference of my circle - pi*d)
    so for my power I got .0489^2/.0207 = .1155
    Then I thought I would just plug that number into the third equation
    E = .1155w(.45s)
    which would give me .052 J
    but this isnt the right answer.
    Where did I go wrong?
  2. jcsd
  3. Feb 7, 2016 #2


    User Avatar

    Staff: Mentor

    The method and numbers look okay to me.
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