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Homework Help: The current in a series RL circuit

  1. Nov 23, 2012 #1
    1. The problem statement, all variables and given/known data

    The current in a series RL circuit increases to 20% of its final value in 3.4μs. If L = 2.0mH, what is the resistance R?

    2. Relevant equations

    I=I_0(1-e^(-t/(L/R))) <----Im not sure if this equation is right?

    3. The attempt at a solution

    I'm unsure how to start this problem, or if I'm on the right track with this equation?
  2. jcsd
  3. Nov 23, 2012 #2


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    Neither do I, but assuming it is...
    In terms of the variables in that equation, what would be the final value, and what would be the value after 3.4μs?
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