Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Converting Thermal Conductivity to Thermal Conduction/Resistance

  1. Aug 12, 2009 #1
    Hi all

    I want to convert thermal conductivity to thermal conductance. The problem is with the units.

    for thermal conductivity the units are [W/(m.K)] and for thermal conductance the units are [W/K]

    For E.g for copper thermal conductivity is 400[W/m.K]
    how can I convert it to thermal conductance?Can it be simply by multiplying it my the length of the copper wire I am using?

    Any help with be really appreciated.

    Thanks and Regards
  2. jcsd
  3. Aug 12, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi Hamza! :smile:

    You can always rely on the units …

    just multiply by the length (in metres) …

    "/m" means exactly what it says :biggrin:
  4. Aug 12, 2009 #3
    hmm.. I think you need to multiply by the cross-sectional area and then divide by the length. The conductance should decrease with increased length and increase with larger area.

    Consider if you add a second wire of equal size. You would expect the conductance to increase by a factor of 2 (and resistance drop by a factor of 2).
  5. Aug 13, 2009 #4


    User Avatar
    Science Advisor
    Homework Helper


    oops! :redface: davidrit :smile: is right!

    (I thought the thermal conductivity was of the wire, but I see now it's of the material … see http://en.wikipedia.org/wiki/Thermal_conductivity)
  6. Aug 13, 2009 #5
    Thanks all...
    very much appreciated.
    I have a further query now which I have posted separately.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook