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Homework Help: Quick thermo problem[just an uncertainty]

  1. Jul 20, 2010 #1

    K29

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    1. The problem statement, all variables and given/known data
    A semi-conducting thermistor has a resistance that veries with temperature as follows:
    [tex]R(T)=R_0 exp[\frac{B}{T}][/tex]
    What are the SI units of the calibration constants [tex]B[/tex] and [tex]R_0[/tex]

    This is just the intro chapter to my second thermodynamics course. Anyway, I'm not sure how to start off. I mean I've eliminated dimensional analysis as a way of going about things. I can see its almost an exponential decay formula. All I need is a clue or something :)
     
  2. jcsd
  3. Jul 20, 2010 #2

    Doc Al

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    Staff: Mentor

    Mathematically, what must be the units of any argument to an exponential function? (I assume you meant R0eB/T.)
     
  4. Jul 20, 2010 #3

    K29

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    Ok the units of the exponential function must be unitless. So B is temperature so that it cancels with T. And that leaves [tex]R_0[/tex] to be Resistance in ohms! Right? Thank u.
     
  5. Jul 20, 2010 #4

    Doc Al

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    Staff: Mentor

    Right! :wink:
     
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