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 energy calculation

  1. Jun 20, 2009 #1
    1. The problem statement, all variables and given/known data
    We must calculate the Fermi energy of metallic potassium at 0K. We have aleady found the number of atoms per m cubed, we are told that each atom contributes one electron to the free electron gas.

    2. Relevant equations

    Fermi energy = ((hbar^2)/2m)(((3Pi^2)N)/V)^3/2

    3. The attempt at a solution
    My problem is that i dont know what V is supposed to be. I thought that since each K gives one electron to become K+, V might be +e, but that gave a nonsensical answer.
  2. jcsd
  3. Jun 21, 2009 #2
    Need more info? better explanation?
    Pls help!
  4. Jun 21, 2009 #3


    User Avatar
    Homework Helper
    Gold Member

    You don't need to know V, since the formula involves V only in the form N/V, i.e. the number of electrons per unit volume.
  5. Jun 21, 2009 #4
    ooooooooooooooh, V for volume. Thankyou, i was stuck on thinking voltages.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook