Capacitor with a dielectric: studying for an exam

[mariexotoni]

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

 

[gneill]

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.