The capacitance of a parallel plate capacitor with air as medium is $6\mathrm{\mu F}$ With the introduction of a dielectric medium, the capacitance becomes $30\mathrm{\mu F}$ The permittivity of the medium is $\left({\mathrm{\epsilon }}_0=8.55\times {10}^{-12}{\mathrm{C}}^2{\mathrm{N}}^{-1}{\mathrm{m}}^{-2}\right)$