1. The problem statement, all variables and given/known data Find the electric field everywhere for the following permanently polarized structures which do not support any free charge: (b) Permanently polarized slab [itex]P_0 i_x[/itex] of thickness [itex]b[/itex] placed between parallel plate electrodes in free space at potential difference [itex]V_0[/itex] 2. Relevant equations [itex]D = ε_0 E + P[/itex] [itex]D = εE[/itex] 3. The attempt at a solution [itex]E_0(s-b) + E_i b = V_0[/itex] where E_0 is the electric field outside the slab and E_i is the electric field inside the slab. [itex]εE_i = ε_0E_0 + P_0[/itex] From here I was thinking, since I have a coupled equation, I would solve for [itex]E_i[/itex] and [itex]E_0[/itex] but I don't know if the above method will work since the value of ε was not given. Thanks for the help!