1. Not finding help here? Sign up for a free 30min 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!

Temperature variation of resistance

  1. Feb 8, 2009 #1
    1. The problem statement, all variables and given/known data
    A metal wire has a resistance of 8.10 at a temperature of 20°C. If the same wire has a resistance of 11.45 at 90°C, what is the resistance of the wire when its temperature is -20°C?


    2. Relevant equations
    R=R(o)[1+alpha(T-To)]
    alpha=R-Ro/Ro(T-To)


    3. The attempt at a solution
    alpha=11.45-8.1 / 11.45(70) = 4.18e-3
    R=11.45[1+(4.18e-3)(-40)] = 9.54 ohms
    But 9.54 isnt the answer...
     
  2. jcsd
  3. Feb 8, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    Isn't the resistance at 20° = 8.1?
     
  4. Feb 8, 2009 #3
    Hmm.. I did that and got 6.746. It says I am within 10% of the correct value
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Temperature variation of resistance
  1. Resistance temperature (Replies: 1)

Loading...