Question $5$

An insulating material $2$ cm thick and $200c{m}^2$ in area is to be heated by dielectric heating. The material has relative permittivity of $5$ and power factor of $0\mathrm{.}05.$ Power required is $400$ W and frequency of $40$ MHz is to be used. Determine the necessary voltage and the current that will flow through the material. If the voltage were to be limited to $700$ V $,$ what will be the frequency to get the same power? Absolute permittivity $=8\mathrm{.}854{10}^{-12}\frac{F}{m}.$