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Find the voltage across the resistor

  1. Oct 24, 2016 #1
    1. The problem statement, all variables and given/known data
    A battery with scriptE.gif = 12.0 V and internal resistance r = 1.0 Ω is connected to two 6.9 kΩ resistors in series. An ammeter of internal resistance 0.50 Ω measures the current, and at the same time a voltmeter with internal resistance 10.0 kΩ measures the voltage across one of the 6.9 kΩ resistors in the circuit. What do the ammeter and the voltmeter read?

    2. Relevant equations
    V=IR

    3. The attempt at a solution
    So I found the ammeter reading where Itotal=1.09mA which was correct.
    For the voltmeter reading, I got:
    V=Itotal*6.9kΩ=7.52V which was incorrect. Anyone care to help?
     
  2. jcsd
  3. Oct 24, 2016 #2

    phinds

    User Avatar
    Gold Member
    2016 Award

    Help what? You haven't shown any work, just answers. That's not the way it works here.
     
  4. Oct 24, 2016 #3
    Ammeter reading:
    Rparallel=[(1/6.9k)+(1/10k)]-1=4082.84
    Rtotal= 6.9kΩ+4082.84Ω+1Ω+.5Ω=10984.34Ω
    Itotal=V/R=12/10984.34=.00109A

    Better?
     
  5. Oct 24, 2016 #4
    Ah, I got it it's V=ItotalRparallel
     
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