I've been thinking about this problem a while and can't seem to get anywhere. A charged dielectric plate of thickness t has permittivity e. The 2 surfaces each have a surface charge density +s. Obtain an expression for the electric field inside the dielectric. I think the answer is be that there is no field within the dielectric, as the field contributions from the two sides of the plate are equal but in opposite directions. But this seems to simple. Am I correct or have I completely missed something out?