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Homework Help: Compound Circuits and resistance in a parallel circuit

  1. Nov 11, 2012 #1
    1. The problem statement, all variables and given/known data
    http://imageshack.us/a/img829/1351/circuite.png [Broken]
    Find the current through R3 and R2.

    The resistance of R2 and R3 are 3.00 Ω, so the total resistance should be 9.00 Ω.

    I = 80.0 V / 9.00 Ω = 8.89 A

    2. Relevant equations

    I = E/R (I think?)

    3. The attempt at a solution

    Not really sure where to go from here, since this was the first question of this unit and it's a correspondence course and the book doesn't explain compound circuits past a single paragraph.

    Any supplemental information or hints you can provide?

    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Nov 11, 2012 #2

    Doc Al

    User Avatar

    Staff: Mentor

    So far, so good. What's the voltage across R2 and R3?
  4. Nov 11, 2012 #3
    V = I*R

    V = (8.89 A) (3.00 Ω) = 26.67 V, right?
  5. Nov 11, 2012 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Good! Now use that to find the current through each resistor.
  6. Nov 11, 2012 #5
    Awesome man, thanks a lot.

    R3 = 26.67 V / 12.00 Ω = 2.22 A

    R2 = 26.67 V / 4.00 Ω = 6.67 A
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