$7\mathrm{.}27$ At $2$ GHz$,$ the conductivity of meat is on the order of $1($S$/$m$).$ When a material is placed inside a microwave oven and the field is activated, the presence of the electromagnetic fields in the conducting material causes energy dissipation in the material in the form of heat. $($a$)$ Develop an expression for the time$-$average power per mm$3$ dissipated in a material of conductivity if the peak electric field in the material is E$0.($b$)$ Evaluate the result for an electric field E$0=4104($V$/$m$).$