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!

Conduction heat transfer mechanisms

  1. Dec 8, 2008 #1
    1. The problem statement, all variables and given/known data[/b
    the ends of a 20cm long,2cm diameter rod are maintained at 0degrees and 100degrees by immersion in an ice-water bath and boiling water. heat is conducted through the rod at 4.5x10^4J/h. of what material is the rod made?

    2. Relevant equations


    3. The attempt at a solution

    i first changed the heat energy conducted into watts which is = J/s


    then i found the surface area of the rod


    now plug it into Q/dt=k(A/L)dT


    with this number i found that the rod is made of ice which has a k value of 1.7 (the closest number) but i checked the back and it suppose to be iron which has a k value of 80.. what did i do wrong?
  2. jcsd
  3. Dec 8, 2008 #2
    Your area is incorrect:
    A in this equation is the cross sectional area of the conducting rod... not the entire surface area.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook