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The current in an inductor when energy is stored. Please help

  1. Nov 25, 2012 #1
    The current in an inductor when energy is stored. Please help!!!

    1. The problem statement, all variables and given/known data

    What's the current in a 15mH inductor when the stored energy is 42μJ

    2. Relevant equations

    E = 1/2 L i^2

    3. The attempt at a solution

    .000042J = (.5)(.015H)(i^2)
    .000042J = (.0075)(i^2)
    .0056 = i^2
    √ (.0056) = i
    .0748331 = i

    I need to put the answer in with only two sig figs so i put in .07 but it was wrong :grumpy:
    What am I doing wrong?
     
  2. jcsd
  3. Nov 25, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi BryceHarper! :smile:
    .07 is two decimal places but only one significant figure :wink:
     
  4. Nov 25, 2012 #3
    Re: The current in an inductor when energy is stored. Please help!!!

    I'm dumb haha. Thanks!
     
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