Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How they got formula 1.7 from formula 1.6

  1. Mar 20, 2010 #1
    there is no rho in 1.6
    and E dissapeared

  2. jcsd
  3. Mar 20, 2010 #2


    User Avatar

    Staff: Mentor

    I have not the slightest idea what it is all about, but perhaps σρ=1.
  4. Mar 20, 2010 #3
    its about solid state physics and semiconductors
    and there is no rho in 1.6
  5. Mar 20, 2010 #4
    What work have you done so far to find how σ and ρ are related?

    You obviously have gaps in the subject and should review EM before continuing on. It's such a simple relationship.
  6. Mar 20, 2010 #5
    [tex]\sigma =\frac{ne^2\tau }{m}[/tex]

    [tex]E =\rho J[/tex]

    [tex]\tau=\frac{m}{\rho n e^2}[/tex]
    Last edited: Mar 20, 2010
  7. Mar 20, 2010 #6
    here is a hint.

    What is definition of σ?

    What is definition of ρ?

    can you find this out please.
  8. Mar 20, 2010 #7
    thanks :)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook