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Homework Help: Equivalent resistance if the values of the two resistances

  1. May 2, 2009 #1
    Two resistors are in series. Find the equivalent resistance if the values of the two
    resistances are as follows.
    a) 10 [Ω] and 20 [Ω].
    b) 100 [Ω] and 1 [MΩ] (M stands for “Mega” or million).
    c) 3.0 [kΩ] and 6.7 [kΩ] (k stands for “kilo” or thousand).
    d) 400 [Ω] and 1 [Ω].

    Repeat the above problem, assuming that the resistors are in parallel.

    Can anybody hel me with this, please? I have no idea how to start/do this. :confused:

    Thank you!
  2. jcsd
  3. May 3, 2009 #2


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    Homework Helper

    Re: resistors

    To start you off, what do you know about how to find equivalent resistance of resistors in series and parallel?
  4. May 3, 2009 #3
    Re: resistors

    parallel has the same voltage and the current in series stays the same?
  5. May 3, 2009 #4


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    Re: resistors

    Series resistors:



    Parallel resistors:

    ( 1/ Requivalent) = ( 1 / R1) + ( 1/ R2) +........+ ( 1/ Rn)

    OR you can use the following equation if you have two parallel resistors:

    Requivalent=[tex]\frac{R1 \times R2}{R1 + R2}[/tex]
    Last edited: May 3, 2009
  6. May 5, 2009 #5
    Re: resistors

    So I just add them? a) would be 30 then.
    Thank you, that works:)
    Last edited: May 5, 2009
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