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Dimensional formula for h

  1. Nov 22, 2013 #1
    Good day. Forum newbie / physics rookie here.

    I need the dimensional formula for Planck

    5p3ll!ng is not my strong suite...but I can quantify "5p3ll!ng" to the nth degree.
  2. jcsd
  3. Nov 22, 2013 #2
    Sorry, cell phone typo...

    The dimensional formula for Planck's Constant... m? L? T?
  4. Nov 22, 2013 #3


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    What about using wikipedia?

    A good way to remember the dimension of h is the uncertainty principle. xp, Et, lθ, etc. all have the same dimension as h.
  5. Nov 22, 2013 #4
    Thanks kith...

    Have you looked at the Wikipedia page for the Planck Constant and found the dimensional formula? It's not there.

    Also, google produces inconsistent responses.

    I'm assuming h = m L^2 T^-1

    However, assumptions will land me in algebraic purgatory. I'll review your response to verify my assumption...
  6. Nov 22, 2013 #5


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    Yes it is. It says "Js" numerous times. You could have arrived there also by considering my hint [h]=[E][t]=Js. Also Js = kg m² / s, so your assumption is correct.
  7. Nov 22, 2013 #6
    kith: I asked a simple straight-forward question that has a difinitive answer. You gave me homework. I even said "physics rookie".

    You can lead a horse to water, but you can't make a physics rookie drink mass, length, and the reciprocal of time by offering hints that the uncertainty principal has ANYTHING to do with joules multiplied by time.

    That's for future reference.

    Thanks for confirming my assumption...I'm going to take your lesson to heart so I can move on from my rookie status. :)
  8. Nov 22, 2013 #7


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    I was trying to understand what prevented you from solving the simple question by using wikipedia. Physics is not so much about answers but about how you get there. Sorry for assuming that you wanted to understand. ;-)

    Why not just ask about the hint if you don't understand it? The uncertainty principle for energy and time reads ΔEΔt ≥ ħ/2. The right-hand side has the dimension of h, so the left-hand side needs to have the same dimension as h. This tells you that the dimension of h is Js.
  9. Nov 22, 2013 #8
    Why not ask about the hint?

    Because math & physics gurus are notoriusly "holier than thou". Asking about hints often leads me to long-winded discusions and complex formulas that confuse the issue even futher.

    That's why I prefer industrial arts. :)
  10. Nov 22, 2013 #9


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    Staff: Mentor

    Around here we tend to take seriously the parable about giving a man a fish versus teaching him how to fish. :wink:
  11. Nov 22, 2013 #10
    jtbell: when dealing with a rookie fisherman, do you hand him a shovel and expect he should know that it's used to dig for worms?

    Teaching a rookie means walking him through the process.

    Again: "holier than thou".
  12. Nov 22, 2013 #11

    Vanadium 50

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    The question has been asked and answered, and has derailed. Closed.
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