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Homework Help: Equivalent Resistance

  1. May 9, 2010 #1
    1. The problem statement, all variables and given/known data
    http://img265.imageshack.us/img265/9245/45050879.png" [Broken]


    2. Relevant equations



    3. The attempt at a solution
    I really just don't know. I understand how equivalent resistance works, but I just don't get this question. Please ignore the marks I have on the page.
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 9, 2010 #2

    rl.bhat

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    Since the ammeter reads zero, that branch can be taken as short circuit or open circuit.
    Now apply equivalent resistance formula to find R.
     
  4. May 9, 2010 #3
    Sorry, but I'm not really sure what you mean by that.
     
  5. May 9, 2010 #4

    rl.bhat

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    Have you heard about the Wheatstone Bridge? What is the balancing condition of the bridge?
    When there is no current in the ammeter, either remove the ammeter from that branch, or replace it by a conductor and find the equivalent resistance of the circuit.
     
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