Question

Question #7a264

Answer 1

`0.0025m`, rounded to three decimal places.

Explanation:

Size of penny is `0.75` inches (`19.05` mm) in diameter.

Capacitance `C` of a parallel plate capacitor as shown in the figure below is given by the expression

`C=(kepsilon_0A)/d`
where `epsilon_0=8.854xx10^-12Fcdot m^-1` 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
`10^-12=(8.854xx10^-12xx[pi(19.05/(2xx1000))^2])/d`
`d=8.854xxpi(19.05/(2xx1000))^2`
`d=0.0025m`, rounded to three decimal places.