Question #7a264

1 Answer
Feb 26, 2017

0.0025m, rounded to three decimal places.

Explanation:

Size of penny is 0.75 inches (19.05 mm) in diameter.
![wikimedia.org/wikipedia/commons](useruploads.socratic.org)
Capacitance C of a parallel plate capacitor as shown in the figure below is given by the expression
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C=kε0Ad
where ε0=8.854×1012Fm1 is permittivity of space and k is relative permittivity of the dielectric material between the plates. k=1 for free space, k>1 for all media, 1 for air.

Assuming that the pennies are kept in air, inserting given values we get
1012=8.854×1012×[π(19.052×1000)2]d
d=8.854×π(19.052×1000)2
d=0.0025m, rounded to three decimal places.