- #1
kilwan
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Homework Statement
d=10cm; U=180kV; er1=5; Ep1=50 kV/cm; Ep2=30 kV/cm; Ep=breakdown strength.
So you have a Parallel Plate Capacitor with two layers between the plates. One is air and it has the Ep2=30kV/cm, the other one has a Ep1=50 kV/cm and a relative permittivity of 5. The capacitor is on a voltage of 180k and you have to calculate the diameter of the second layer (with the Ep1) so that it doesn't come to an breakdown.
Homework Equations
U=U1+U2=[tex]\frac{Q}{e0*S}[/tex]*([tex]\frac{d1}{er1}[/tex]+[tex]\frac{d2}{er2}[/tex])
U1=E1d1
U2=E2d2
The Attempt at a Solution
Witch ever formula i use i end up have to many unknown variables. But i think i should calculate the critical Q and then get the S or the out of the formula for the eletric field of the layer.