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Homework Help: Power, Potential, Emf

  1. Apr 3, 2007 #1
    1. The problem statement, all variables and given/known data

    A wire of resistance 5.0 Ω is connected to a battery whose emf ε is 2.0 V and whose internal resistance is 1.0 Ω. In 2.0 min, how much energy is (a) transferred from chemical to electrical form in the battery, (b) dissipated as thermal energy in the wire, and (c) dissipated as thermal energy in the battery?


    2. Relevant equations

    P=iV
    P=i^2r
    P=iE(the fancy E)
    Vb-Va=(E/(R+r))R
    i=E/(R+r)


    3. The attempt at a solution

    I am having trouble finding the current, so I cannot find power.
    I am using i=2.0V/(5.0+1.0)=0.333A
    then I get Vb-Va=(0.333Ax5.0)
    the answer for part a) is 80J
    when I use P=iV I don't get that answer...

    If I could make it more clear...I can, just post!
     
  2. jcsd
  3. Apr 3, 2007 #2
    nevermind, I figured it out on my own

    BOARD CLOSED
     
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