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KillerZ
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Homework Statement
Air "breaks down" when the electric field strength reaches 3 x 10^6 N/C, causing a spark. A parallel-plate capacitor is made from two 4.0cm-diameter disks. How many electrons must be transferred from one disk to the other to create a spark between the disks?
Homework Equations
Q = [tex]\epsilon[/tex]0AE
N = Q/e
The Attempt at a Solution
Ok, I think this is right but I am not sure:
Q = [tex]\epsilon[/tex]0AE
A=[tex]\pi[/tex]r^2
=(8.85x10^-12 C^2/Nm^2)([tex]\pi[/tex](0.02m)^2)(3x10^6 N/C)
=3.3x10^-8 C = 33nC
N = Q/e
= (3.3x10^-8 C)/(1.60x10^-19 C/electron)
= 2.1x10^11 electrons