Parallel plate capacitor and insulating material

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Homework Statement



A parallel-plate capacitor has plates of 10 cm^2 area separated by a 0.10mm layer of glass insulation with resistivity rho = 1.2x10^13 omega*m and dielectric constant k= 5.6. Because of the finite resistivity, current can leak through the insulation.

How do I Show that it depends only on the properties of the insulating material and not on its dimensions?

Homework Equations



C= emf(A/d)


The Attempt at a Solution


I found the time constant for this capacitor to discharge through its insulation. T= 590s
 

Answers and Replies

  • #2
LowlyPion
Homework Helper
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Homework Statement



A parallel-plate capacitor has plates of 10 cm^2 area separated by a 0.10mm layer of glass insulation with resistivity rho = 1.2x10^13 omega*m and dielectric constant k= 5.6. Because of the finite resistivity, current can leak through the insulation.

How do I Show that it depends only on the properties of the insulating material and not on its dimensions?

Homework Equations



C= emf(A/d)


The Attempt at a Solution


I found the time constant for this capacitor to discharge through its insulation. T= 590s

Consider the resistivity

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/resis.html#c2

Consider too the equation you have for capacitance.

Notice anything about how - when you combine the 2 - the RC has a tendancy not to be dependent on the cross sectional area?
 

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