A parallel plate capacitor is to be designed which is to be connected across $1 \mathrm{kV}$ potential difference. The dielectric material which is to be filled between the plates has dielectric constant $K=6\pi$ and dielectric strength ${10}^7 \mathrm{V} {\mathrm{m}}^{-1}$. For safety, the electric field is never to exceed $10\%$ of the dielectric strength. With such specifications, if we want a capacitor of capacitance $50 \mathrm{pF}$, what minimum area (in ${\mathrm{mm}}^2$) of plates is required for safe working?

$\left(\text{use }{\epsilon }_0=\frac{1}{36\pi }\times {10}^{-9} \text{in }\mathrm{MKS}\right)$