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!

A Is this an application of the Virial theom?

  1. Jul 3, 2017 #1
    The problem concerns a liquid column (assume infinitely long) with radius R connected to an electric potential V, the liquid thus has certain surface charge density.
    A small perturbation may change the surface profile of the cylinder (small compared to R) and thus change its surface charge density.
    This change causes electric energy of the liquid column to change by E, then the energy change of the charging system is -2E, making the total electrical potential change E-2E = -E. Can Virial theorem explain this result? If not what theorem (or calculation) explains it?
  2. jcsd
  3. Jul 3, 2017 #2


    User Avatar
    Science Advisor
    Gold Member

    Isn't the virial theorem used in dynamics, not statics problems? Maybe you're confusing it with calculus of variations?
  4. Jul 3, 2017 #3
    Thanks for your reply. I am dealing with a problem of instability of an infinitely long charged liquid jet. When there is a change is surface profile(which originally is a column with radius R), the electric energy change of the liquid jet is E, the charging system (a constant voltage V connected to the liquid jet) has energy change -2E, the paper I am reading just gives this result without proving it. So I am trying my luck here to see if any theorem can explain it.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted