1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: 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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook