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Homework Help: Please explain what I am doing wrong

  1. May 20, 2010 #1
    What am I doing wrong in this problem? Please explain to me what I am doing wrong. Thanks
    h-bar is plank's constant.

    E = (l(l+1)(h-bar^2))/2I (l = 1)

    I = Mh*R^2 Mh = 1.67x10^(-24)g R = 161x10^(-10) cm

    For I i got 4.33x10^-40

    So when i plugged in I for the top equation, i got E = (1(1+1)(1.11x10^(-68)))/8.66x10^-40
    which equaled to : 2.56351... x 10^-29
    But I found out from a friend that E actually equals to -2.18x10^(-18) Joules

    What am I doing wrong?
  2. jcsd
  3. May 20, 2010 #2


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    It would help if you told us what the actual problem is. All I see is you plugging random numbers into random equations.

    Edit: Okay, it makes more sense with a bit of formatting.
    You need to keep track of your units. You're not using SI units everywhere, so your answer isn't going to come out in Joules.
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