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: Three Kind of electrostatics problem(quite )

  1. Mar 18, 2008 #1
    Three Kind of electrostatics problem(quite urgent)

    1. The problem statement, all variables and given/known data
    The first kind of prbolem is about the dielectric coefficient

    I know the equations below
    but I don't know how to relate the E-field into eqn1
    The main reason is that I don't know is the D related in this kind of problem?

    2. Relevant equations
    [tex]\frac{tan\alpha1}{tan\alpha2}[/tex] = [tex]\frac{K1}{K2}[/tex]
    where alpha1 is incidence angle
    K is dielectric coefficient

    where D is electric displacement
    E is E-field


    where [tex]\epsilon[/tex]o is the permittivity of dielectric
    [tex]\epsilon[/tex] is the permittivity of vaccum

    1. The problem statement, all variables and given/known data
    The second type of problem is about the simplest electrostatic problem!!!!!!!
    I don't really understand the meaning of "potential" is zero.
    Doesn't the potential is set by us?
    I know that when the net force is zero, then the PE should be minimum.
    But these problems make me very confusing.

    1. The problem statement, all variables and given/known data
    The last kind of question is about the leakage and capacitance.

    The equation related:
    where [tex]\sigma[/tex] is lossy dielectric of conductivity

    I cannot really remember the previous concept of capacitance very well
    but I know that the time constant(decay to half ) is RC

    this problem are something new for me
    and I wanna know how to use the idea of lossy dielectric of conductivity
  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