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: Thermodynamics - maximalization of temperature

  1. Oct 14, 2012 #1
    1. The problem statement, all variables and given/known data
    We have three metal cubes, the same material, same size. Two cubes
    have temerature 300K, third 100K.

    On what maximal temperature can
    we heat the on of the cubes?

    3. The attempt at a solution
    If we want to get higher temperature than 300K we need to
    use the gradient of temperatures two cubes to get some work,
    which we can after use to heating the third cube. I tried to place
    ideal heat machine, which work on base of carnot cycle between
    the two cubes (one 300K other 100K) - but I just have two temperatures
    and on wiki is written, that to work from carnot cycle I need entrpy too.
    So I don't know how to continue.

    Thanks for any help.
    Last edited: Oct 14, 2012
  2. jcsd
  3. Oct 14, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Can you post the exact wording of the question? Does the question allow you to use a heat pump or are they just expecting you to apply conservation of energy?
  4. Oct 14, 2012 #3
    I can use heat pump. If I understand well the energy conservation law, then
    the maximal temperature is 300K, any other manipulation will just make
    average (so maximal temperature in the system will be lower) of temperatures . . .
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook