Suppose ,one wishes to construct a`1.0`farad capacitor using circular discs. If the separaton between the discs be kept at `1.0`mm, what would be the rradius of the discs?

Explanation

Let the radius of the disc `= r`
So, `C = eplision_0 A / d = eplision_0 pie r ^(2) / d`
or, `r^(2) = cd / eplision_0 pie`
`= 1 xx 10 ^(-3) / 8.8 xx 10^(-12) xx 3.14 `
`= 0.36 xx 10^(8)`
`r = 6.0 xx 10 ^(2) = 6 km.