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Find the current and potential difference

  1. Mar 11, 2011 #1
    1. The problem statement, all variables and given/known data
    For the circuit shown in the figure, find the current through and the potential difference across each resistor.
    http://session.masteringphysics.com/problemAsset/1169464/1/jfk.Figure.23.P60.jpg


    2. Relevant equations
    V=I(amps)/R(ohms) and Req=R1+R2+R3.....


    3. The attempt at a solution
    Rearranging the circuit:
    R(8ohm) and R(24ohm) are parallel so (1/8+1/24)^-1=6ohm
    that created a series of R(6ohm)+R(6ohm) so R6+R6=R(12ohm)
    now I have the first circuit R(4ohm) in parallel with R(12ohm) and R(24ohm)
    (1/4+1/12+1/24)^-1=2.67ohm for equivalent resistance for the entire circuit

    24V=I*2.67ohm
    I=9Amps

    across the 4ohm resistor the current is? I=9A because the current is the same or is it 9A divided across the 3 parallel resistors?

    I'm either getting it wrong because I put the 4ohm by itself (before the junction correct?) or if it's in series with the 2 6ohm resistors then that's my error but I've definitely tried it 4 different ways and am getting something wrong.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 11, 2011 #2

    SammyS

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    See the comment in red.
     
  4. Mar 11, 2011 #3
    so 4ohm in series with (1/12+1/24)^-1 which equals 8ohm

    4ohm+8ohm (series)=12ohm for the entire circuit

    24V=12ohm*I
    I=2amps
     
    Last edited: Mar 11, 2011
  5. Mar 12, 2011 #4

    SammyS

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    Yes.

    Now, work your way back through all the resistors.
     
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