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Series wiring problem

  1. Oct 13, 2005 #1
    How do, everyone. I'm 99% done with my HW set for this week and am stuck on this problem.

    Three resistors are connected in series across a battery. The value of each resistance and its maximum power rating are as follows: 5.0 Ohms and 19.5 W, 32.0 Ohms and 10.0 W, and 15.0 Ohms and 10.0 W.

    (a) What is the greatest voltage that the battery can have without one of the resistors burning up?
    I've correctly found this value to be 28.6V.

    (b) How much power does the battery deliver to the circuit in (a)?


    I can't figure it out. I've tried using multiple equations (variations of P=IV), using a current of 0.55A and V^2/R=P, using V=28.6V, R=52 Ohms (total for series). Also tried P=(I^2)*R. All three equations yield a power of 15.73W...as they should, considering they are all derived from one another :approve: . This, however, is not the correct answer.

    So where is my thinking going wrong here?

    Thanks in advance :rolleyes:
  2. jcsd
  3. Oct 13, 2005 #2
    Sorry. The answer was correct. Apparently the system has started utilizing sig figs. More than welcome to kill this post.

    Thanks for looking if in fact you did!
  4. Oct 13, 2005 #3
    how did you figure out the first part???? i have close to the same problem but with different values, but i am kind of lost
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