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

  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. tiny-tim

    tiny-tim 26,041
    Science Advisor
    Homework Helper

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

    I'm dumb haha. Thanks!
     
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