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Homework Help: Electrical Resistance

  1. Jan 23, 2008 #1
    1. The problem statement, all variables and given/known data
    In Fig. 27-29, R1 = 85.8 Ω, R2 = R3 = 67.5 Ω, R4 = 89.7 Ω, and the ideal battery has emf ε = 6.0 V. (a) What is the equivalent resistance? What is i in (b) resistance 1, (c) resistance 2, (d) resistance 3, and (e) resistance 4?


    2. Relevant equations

    I in = I out

    3. The attempt at a solution

    I don't even know where to begin with this problem. I can't figure out how to use the formula of I in = I out with this problem.
  2. jcsd
  3. Jan 23, 2008 #2
    For a)

    you can see R2, R3, and R4 are all in parallel, so you can find an equivalent resistance for those three, and R1 is in series with that equivalent resistor, so you can find the equivalent resistance. Does that get you going?

    The second part asking for the currents can be done with Kirchoff's laws and Ohm's Law
  4. Jan 23, 2008 #3
    R2, R4, & R3 are in parrallel, find the equivilent R for those seperate, then take what you got for that and then find the equivilent R for a series using what you got before as well as R1. That should get you started with the first part.

    Whoops, looks like someone beat me to it. :)
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