The space between the plates of a parallel-plate capacitor is filled with two slabs of linear dielectric material. Each slab has thickness s, so that the total distance between the plates is 2s. Slab 1 has a dielectric constant of 2, and slab 2 has a dielectric constant of 1.5. The free charge density on the top plate is o and on the bottom plate is -o. The electric field in slab 2 is equal to to