A parallel plate capacitor is constructed with a dielectric slab with Kappa = 1.
ID: 1327584 • Letter: A
Question
A parallel plate capacitor is constructed with a dielectric slab with Kappa = 1.5 inserted between the plates. The area of each plate is 5 cm^2, and the distance between the two plates is 1 mm. Assume the infinite plane approximation.
1. If we fix the charge on the capacitor to be Q = 6E-11 C, what is the potential difference between the top and bottom plates? Note that in the region containing the dielectric medium, the electric field is E = E0 / Kappa, where E0 is the electric field in a vacuum. (Also, what does it mean by electric field in a vacuum?)
2. What is the capacitance of this configuration? Note: 1 pF = 10^-12 F
Please show complete work and also describe your reasoning and process.
Explanation / Answer
Here ,
1)
as the electric field is given as
E = Q/(area * epsilon)
E = 6 *10^-11/(5 *10^-4 * 1.5 * 8.854 *10^-12)
E = 9035.4 N/C
the electric field in the capacitor is 9035.4 N/
2)
Capacitance , C = Q/V
C = Q/(E * d)
C = 6 *10^-11/(9035.4 * 0.001)
C = 6.641 *10^-12 F
the capacitance for this configuration is 6.641 pF