- #1
Destroxia
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Homework Statement
The plates of a spherical capacitor have radii 51.8 mm and 55.0 mm. (a) Calculate the capacitance. (b) What must be the plate area of a parallel-plate capacitor with the same plate separation and capacitance?
(givens)
a = 51.8 mm
b = 55.0 mm
d = 3.2 mm
ε0 = 8.85E-12
(unknown)
Part a:
Csphere = ?
Part b:
A (plate area of parallel-plate capacitor) = ?
Homework Equations
(Spherical Capacitor) Csphere = 4πε0 * [(a*b)/(b-a)]
(Parallel Capacitor) Cparallel = (ε0*A)/d
Csphere = Cparallel
The Attempt at a Solution
Csphere = 4π(8.85E-12[F/m]) * ((51.8[mm]*55.0[mm]*E-6)/((55.0[mm] - 51.8[mm])*E-3))
= 9.896E-11 F
= 98.86 pF
I could easily solve the second part just by plugging in this capacitance for the parallel-plate capacitor, but the program I am plugging the answer into tells me my answer is wrong. I have double checked the answer, even triple checked the answer, it seems to be coming down to some calculation error?