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Homework Help: Power disspation

  1. Jul 2, 2010 #1
    What is the value of unknown emf in this pic plz help me?

    [PLAIN]http://www.atiani.com/int.gif [Broken]
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jul 3, 2010 #2
    just sum up the power dissipations from a to b, for resistors use I^2*R, for voltage sources use I*V and pay attention to the sign of of the source (a drop in the direction of I is +V, gain -V).
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