The permittivity of vacuum `epsi`o is equal to
`1/(4pixx9xx10^9)` C-2N+1m+2
`1/(4pixx9xx10^9)`C2N-1m-2
9 `xx` 109 C2N-1m-2
9` ` `xx` 109 C-2N1m+2
can u tell me how t comes