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Homework Help: Capacitor with a dielectric: studying for an exam

  1. Apr 30, 2012 #1
    Okay so I have a parallel-plate capactior
    k=5.5
    Area= .034m^2
    Plate Separation= 2mm
    If the Electric Field falls short, the capacitor will burn up if exceeding 200kN/C.

    It's asking for the max energy stored by the capacitor.


    My attempt was lame.
    I tried using
    C= (ε0)A/d

    and since it's a dielectric, i replace ε0 with ε0k

    Also I used
    U= .5CV^2
    Replacing V with E/d
     
  2. jcsd
  3. Apr 30, 2012 #2

    gneill

    User Avatar

    Staff: Mentor

    For a capacitor the field magnitude in a dielectric is not the same as the field magnitude in free space. So you might want to think a bit more about how the dielectric will affect things.
     
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