Determine the dielectric constant

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SUMMARY

The discussion focuses on calculating the dielectric constant (K) of a parallel plate capacitor formed by two flat metal circles with a radius of 15 mm and separated by 8.0 mm. The surface charge density is given as +1.0 x 10^-3 microCoulombs/mm², and the potential difference across the capacitor is 0.12 Volts. The capacitance formula C = K * (ε0) * (A/d) is utilized, where A is calculated as πr². The user attempts to find capacitance using the surface charge density but requires further clarification on the relationship between charge, capacitance, and dielectric constant.

PREREQUISITES
  • Understanding of parallel plate capacitor theory
  • Familiarity with the formula for capacitance C = K * (ε0) * (A/d)
  • Knowledge of surface charge density and its relation to charge
  • Basic grasp of dielectric materials and their properties
NEXT STEPS
  • Calculate the area of the capacitor plates using A = πr²
  • Determine the total charge (Q) using the surface charge density
  • Use the relationship Q = CV to find the capacitance (C)
  • Rearrange the capacitance formula to solve for the dielectric constant (K)
USEFUL FOR

Students studying electromagnetism, electrical engineers, and anyone involved in capacitor design and analysis.

jamba88
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Homework Statement


Two flat metal circles of radius r=15 mm are brought a distance d=8.0 mm apart to form a parallel plate capacitor. The surface charge density of one plate is measured to be +1.0*10^-3 microCouloubs/mm^2. The potential difference across the capacitor is measured to be .12 Volts. There is a dielectric between the plates. What is the dielectric constant.


Homework Equations


C=K*(E0)*[A/d]
A=(pi)r^2
Q= CV... maybe


The Attempt at a Solution


I plugged what I had into the equation, but I don't know how to find the capacitance using the surface charge density.
I have
C= K(8.85*10^-12)*[pi*(.015^2)/.008]
 
Physics news on Phys.org
Find the area of the plate(mm2), then multiply that by the density to give charge.
 

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