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Resistance and Voltage, switch diagram

  1. Mar 19, 2015 #1
    1. The problem statement, all variables and given/known data
    Untitled.png

    Untitled.png

    2. Relevant equations
    V=IR


    3. The attempt at a solution
    I said: A>D=F>B=C>G>H=E

    I assumed higher resistance would lead to higher readings. However here are the answers:

    H=E>C=B>G>D>F>A

    Can someone explain to me why this is? As you can see H=E which combined gives a total resistance of (2/3)ohms is, according to the answers, going to give the largest volt meter reading. Why is this true?
     
    Last edited by a moderator: Mar 19, 2015
  2. jcsd
  3. Mar 19, 2015 #2

    SammyS

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    Why assume that? The volt-meter only measures the voltage drop across that one resistor. Its resistance is fixed, so the voltage is proportional to the current through that resistor. Any current supplied by the battery must pass through that resistor, some how is that current related to the overall resistance of the circuit?
    How do you get any particular resistance value?

    No resistance value is given for any of the resistors. Are we to assume that they all have the same resistance?
     
  4. Mar 19, 2015 #3
    OH geesh sorry I feel like a dork I forgot a part of the question here is the explanation:

    Untitled.png
     
  5. Mar 19, 2015 #4

    SammyS

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    untitled-png.80652.png
    You could type some of this out.

    Part of the explanation has been given. We need a response from you. You have over 100 posts, so you should know how things work here.

    How did you arrive at your order? (in addition to having voltage behavior reversed.)
     
  6. Mar 19, 2015 #5
    I am not sure how I had voltage behavior reversed. V = IR so and increase in resistance will increase voltage. If I = 1 and R = 4 then V = 4 if I = 1 and R = 10 then V = 10. 1<10

    However, I did not take into account that the measurement of V was across only one resistor. I am currently trying to work out how to get the V for that one resistor in each configuration.
     
  7. Mar 19, 2015 #6
    Thank you for the insight I understand now!
     
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