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Homework Help: How to find the Dielectric Strength

  1. Nov 28, 2007 #1
    Hello, everyone!

    I have a question, and i don't know how to solve it...
    They ask me for the dielectric strength!
    How do i find it?
  2. jcsd
  3. Nov 28, 2007 #2


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    Homework Helper

    Type out the entire problem so we can help you...
  4. Nov 28, 2007 #3
    The full question is like this:

    The square plates of a 9000pF capacitor measure 90mm by 90mm and are separated by a dielectric which is 0.29mm thick. The voltage rating of the capacitor is 300V. THe dielectric strength, in KV/m is closest to:
    A. 1300
    B. 930
    C. 1200
    D. 1100
    E. 1000

    To be honest i have no idea how to approach this problem.
  5. Nov 28, 2007 #4


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    Homework Helper

    for such a capacitor,the capicitance is given by

    [tex]C=\frac{\epsilon_0 A}{d}[/tex] where d=thickness and A=area
  6. Nov 29, 2007 #5
    ok i did the calculation

    Eo = 8.85 x10^-12
    A= 8.1x10^-3
    d = 2.9x10^-4

    so the final answer is C = 2.4719x10^-10

    Now what should i do?
  7. Oct 12, 2009 #6
    Can u tell me where did u find the problem coz that was the same question in my exam? So that I can predict future exam qts.
  8. Oct 13, 2009 #7
    It was actually in my exam a few years ago.. i solved the problem in class tho... i don't remember the answer, but the equation given here was very useful... :)
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