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Homework Help: Resistance Comparison P & S

  1. Mar 12, 2009 #1
    1. The problem statement, all variables and given/known data

    Two resistors of resistances R1 and R2, with R2 > R1, are connected to a voltage source with voltage V0. When the resistors are connected in series, the current is Is. When the resistors are connected in parallel,the current Ip from the source is equal to 10 Is. Let r be the ratio R1/R2. Find r.

    2. Relevant equations
    Ohm's Law : V = IR

    3. The attempt at a solution

    I sure that I need to use Ohm's Law to compare the resistance but I am not sure how to calculate the resistance of each of them when they were connected in series and then in parallel,

    I know that current is conserved but does this mean that both R1 and R2 have the same current while in series and in parallel?
  2. jcsd
  3. Mar 12, 2009 #2


    User Avatar
    Homework Helper

    Look at the effect of the equivalent resistances.

    For series:

    Req = R1 + R2

    For || :

    1/Req = 1/R1 + 1/R2
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