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Inductive time constant, value of resistance

  1. Jul 9, 2010 #1
    1. A current in an RL circuit rises to one half of its maximum value in 7.0s. a) what is the inductive time constant for the circuit? b) if L= 0.8 H, what is the value of the resistance?

    2. My book says the (time constant) = L/R

    3. I've tried plugging into the above equation, but I know there's something missing, and I don't know what it is.
  2. jcsd
  3. Jul 9, 2010 #2
    What is your equation for the the current in an R-L circuit?
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