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Determing Resistance of metal with temperature coefficient of resistance

  1. Oct 13, 2011 #1
    1. The problem statement, all variables and given/known dataI'm trying to determine R_0 and alpha (temperature coefficient of resistance) from results I obtained through an experiment. We have been given the first equation and been told that R_T is the resistance at temperature T in kelvin. R_273 is the resistance at temperature 273K and alpha is a constant called the temperature coefficient of resistance. I don't know what the material is therefore I have no idea of what alpha should be.


    2. Relevant equations
    1)R_T = R_273(1+alpha(T))
    2)R_T = R_0(1+alpha(T))

    3. The attempt at a solution

    I created the attached graph to try and determine alpha through the gradient of the line, but no matter how i try and derive alpha and/or R_0, I simply can't get an answer that's gives valid results for R_T at other temperatures.
     

    Attached Files:

    Last edited: Oct 13, 2011
  2. jcsd
  3. Oct 13, 2011 #2
    First, I think you want to write your equations in the form:

    R_T = R_0(1+alpha(T - T0))

    so when T = T0, then R_T = R_0

    Then, I would re-arrange your equation into the standard form:

    y = mx + b

    And you can solve for alpha with linear regression or pick two good end-point. Metals get non-linear at cold temperatures (as your graph shows) so stay in the linear region.
     
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