Dielectric Filled Parallel Plate Capacitor Question

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Homework Help Overview

The discussion revolves around a parallel plate capacitor with mylar dielectric, focusing on determining the thickness of the dielectric given specific parameters such as plate dimensions and maximum voltage. The subject area includes concepts from electrostatics and capacitor theory.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants express uncertainty about the equations needed to solve for the dielectric thickness, particularly the role of charge (Q) in their calculations. There are mentions of voltage relationships across the dielectric and the gap, and one participant suggests using the electric field strength in conjunction with dielectric properties.

Discussion Status

Some participants have provided insights into relevant equations and relationships, while others are still grappling with the setup of the problem. There is a mix of attempts to derive a solution and expressions of confusion regarding the necessary parameters.

Contextual Notes

Participants note the absence of the charge value (Q) as a potential barrier to solving the problem. Additionally, there is a suggestion to look up dielectric strength as an alternative approach, which some participants express reluctance to pursue without understanding the calculations involved.

SabreV45
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Homework Statement


A parallel plate capacitor has rectangular plates measuring 44.0 cm by 30.0 cm, and can be charged to 1600 V maximum ΔV without electrical breakdown. The gap between the plates is fulled with mylar dielectric (κ=3.2). Find the thickness of the dielectric.

Homework Equations



C=κC0
C=Q/ΔV
C00(A/d)

The Attempt at a Solution



I believe I am missing an equation needed to solve this question. The way I had this question set up, I wasn't able to solve without a value for Q.
 
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SabreV45 said:

Homework Statement


A parallel plate capacitor has rectangular plates measuring 44.0 cm by 30.0 cm, and can be charged to 1600 V maximum ΔV without electrical breakdown. The gap between the plates is fulled with mylar dielectric (κ=3.2). Find the thickness of the dielectric.


Homework Equations



C=κC0
C=Q/ΔV
C00(A/d)


The Attempt at a Solution



I believe I am missing an equation needed to solve this question. The way I had this question set up, I wasn't able to solve without a value for Q.

The voltage across the dielectric + the voltage across the gap = your total voltage.

Remember in a constant field, voltage is just given as E*d.
And the equation you're missing is :

E(through dielectric) = E0/κ , with E0 the field between the plates without any dielectric.
 
Apphysicist said:
The voltage across the dielectric + the voltage across the gap = your total voltage.

Remember in a constant field, voltage is just given as E*d.
And the equation you're missing is :

E(through dielectric) = E0/κ , with E0 the field between the plates without any dielectric.

Thanks for the info. I'm still not exactly sure how to solve for the thickness of the dielectric.

I'm mainly having problems setting up with question, once I get it set up I'll be able to solve everything myself. I'm just not able to think of a way to solve this question without having the value for Q.
 
Cheat. Look up the dielectric strength for mylar and determine the minimum thickness for 1600V breakdown. :smile:
 
gneill said:
Cheat. Look up the dielectric strength for mylar and determine the minimum thickness for 1600V breakdown. :smile:

I would prefer to be able to understand the calculations needed to determine the thickness of the dielectric. This was a question that I got wrong on a test and am trying to solve them correctly to keep in my records.
 

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