7.3 Forces on Conductors in the presence of dielectrics The force can be calculated as in Section 4.5 Assume the surface charge density is of and, in the dielectric. D So at the surface of the conductor, E=D/Erco T On half of this field originates in the local charge and he other half from charges situated elsewhere So the electric force per unit area on the conductor is equal to E ED=-ErEoe Recall that in vacuum it was: 2062