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!

Find the rate at which its temperature changes

  1. Feb 2, 2005 #1
    ive been working on this problem and i have a solution too, but it doenst work. the reason i know that it doesnt work is because we have to submit our answers to a computer system that tells us if our answer is right or wrong. please help?

    A blackened, solid copper sphere of radius 5.70 cm hangs in a vacuum in an enclosure whose walls have a temperature of 21.0°C. If the sphere is initially at 0.0°C, find the rate at which its temperature changes, assuming that heat is transferred by radiation only. Also assume that the sphere has an emissivity of 1.

    here is what i did:

    Pnet = dQ/dt = mc dT/dt

    one two skip a few and...

    dT/dt = [3eσ(T^4 – T0^4)]/rρc

    its right...but it doenst work!

    please help?
  2. jcsd
  3. Feb 2, 2005 #2
    never mind...i got it...
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Find the rate at which its temperature changes