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!

Homework Help: Fermi distribution of 3s electrons of sodium

  1. Feb 26, 2009 #1


    User Avatar

    1. The problem statement, all variables and given/known data

    What fraction of the 3s-electrons of sodium is found within an energy k_b*T below the Fermi level? (Take room temperature at T= 300k) Fermi level for Na is 3.2 eV

    2. Relevant equations

    F(E) = 1 / {exp((E-E_f)/k_b*T) + 1}

    3. The attempt at a solution

    From what I can tell, do not need to know room temp, or even sodium's fermi level. Simply do (E=Ef-k_b*T) solve through and obtain 1/((e^-1)+1) which ends up being approximately 0.73.

    However, book states the answer is 0.88. Why is this? I do not understand where I am going wrong. Any help would be much appreciated.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted