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!

Change in number of microstates

  1. Nov 17, 2016 #1
    1. The problem statement, all variables and given/known data
    An isolated macroscopic system at 300K absorbs a photon with ##\lambda = 550nm##. What is the relative increase ##\frac{\Delta \Omega}{\Omega}## in microstates.

    2. Relevant equations


    3. The attempt at a solution
    The energy of the photon is ##E = \frac{hc}{\lambda}## so that would be the change in internal energy. And ##dU = TdS - pdV## but I assume ##dV = 0## so ##dU = TdS##.

    ##S = k \ln(\Omega)## so I think ##dS = k d\ln(\Omega)##:

    ##d \ln(\Omega) = \frac{hc}{\lambda T}##
    If that's all ok, I don't know how to get from there to ##\Delta \Omega## or how to get the relative increase in ##\Omega##! Thanks for any help!
     
  2. jcsd
  3. Nov 17, 2016 #2

    TSny

    User Avatar
    Homework Helper
    Gold Member

    You just need to carry out the differential of ##\ln \Omega##. You don't need to find ##\Delta \Omega##, you only need ##\frac{\Delta \Omega}{\Omega}##.
    https://en.wikipedia.org/wiki/Differential_of_a_function
     
  4. Nov 18, 2016 #3
    Thank you for that link! Been trying to find out what it's called when you put a 'd' in front of variables for ages. And how to then actually do something with it. Thanks for your help!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Change in number of microstates
Loading...