Question

To get an idea how big a farad is, suppose you want to make a 1-F air-filled parallel-plate capacitor for a circuit you are building. To make it a reasonable size, suppose you limit the plate area to What would the gap have to be between the plates? Is this practically achievable?

Answer 1

• Gap between the plates
  `8.85* 10^(- 16)\ m`
• No, practically not achievable

Solution:

As per the question:

Capacitance, C = 1 F

Area of the plate of the capacitor, A =
`1\ cm^(2) = 1* 10^(- 4)\ m^(2)`

Now,

To calculate the distance, D between the plates of a parallel plate capacitor:

`C = (\epsilon_(o)A)/(D)`

Thus

`D = (\epsilon_(o)A)/(C)`

where

`\epsilon_(o)` = permittivity of free space

Now,

`D = (8.85* 10^(- 12)* 1* 10^(- 4))/(1)`

`D = 8.85* 10^(- 16)\ m`

This distance much smaller and is practically not possible