Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Solving for power in circuits

  1. Feb 16, 2012 #1
    1. The problem statement, all variables and given/known data

    Three resistors are connected across a battery as shown in the figure. (Let V = 141 V and R1 = R2 = R3 = 204 Ω.)


    (a) How much power is dissipated across the three resistors?
    P1 =
    P2 =
    P3 =

    2. Relevant equations


    3. The attempt at a solution

    I solved for each of the voltages across each resistor. Each resistor is 68 ohms.
    so the equivalent resistance of the circuit is 102 = 68 + 1/[2(1/68)]
    Using that and the voltage 141 I get the current I = 1.38235 A
    Using that I solve for V1 = 94 V and V2 and V3 = 46.999 V

    So to get the power for R1 I would take the voltage 94 and multiply it by the current 1.38235 and get 129.9409 W but the answer is incorrect so I'm not sure what I'm doing wrong. The same goes for P2 and P3 when I do the same thing
  2. jcsd
  3. Feb 16, 2012 #2
    I don't know, your original statement said the resistance was 204, do you have the right values?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook