Calculating the capacitance of a parallel-plate air capacitor

AI Thread Summary
The discussion centers on calculating the capacitance of a parallel-plate air capacitor with two plates measuring 18 cm on each side and spaced 3.5 mm apart, connected to a 3-V battery. The formula used for capacitance is C = εo(A/d), where εo is the permittivity of free space. Initially, the area was incorrectly interpreted as 18 cm² instead of the correct area of 0.0324 m². After correcting the area, the capacitance calculation was resolved successfully. The final capacitance value reflects the accurate dimensions of the capacitor plates.
shandsy
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Homework Statement


A parallel-plate air capacitor is made by using two plates 18 cm square, spaced 3.5 mm apart. It is connected to a 3-V battery.

What is the capacitance?


Homework Equations



C = εo(A/d)



The Attempt at a Solution



εo = 8.854e-12
A = .18 m
d = .0035 m

C = εo (.18/.0035) = 4.55348571e-10 F

This is coming up as the wrong answer. I have no idea what I'm doing wrong.
 
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Never mind, I solved the problem. I read "18 cm square" to mean 18 cm2, but I guess it really meant a square with 18cm sides, so A = .0324 m2. Sorry about that!
 

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