電介質的一些參考。

电介质 Dielectrics: insulating materials, in which the appearance of induced charges reduce the field in the insulator.

原子的电偶极矩 Dipole moment of the polarized atom: p=Zea, a is the displacement of the electron cloud.

极化强度矢量 Polarization: The dipole moment per unit volume of the dielectrics. P=Np

外场中的电偶极矩 Dipole in an external field:

电偶极矩在外场中的能量 The energy of an dipole in external field: U=−qaEcos?=−p⋅E

电偶极矩在外场中受的力 The force on an dipole by external field: F=−∇U=∇?P⋅E?

电偶极矩在外场中受的力矩 The torque on an dipole by external field:
?=P×E

相对电容率（相对介电常数）Relative permittivity
? : In dielectrics, the field is reduced by a factor
? . In capacitors, E=E0/?=?/?0C=?0Ad.

电极化率electric susceptibility ?E： ?E=?−1. The relation between polarization and electric field isP=?E?0E, P=?−1?0E.

宏观极化电荷密度 Macroscopic polarization charge density:
?P=−∂Px∂x−∂Py∂y−∂Pz∂z=−∇⋅P.

电位移矢量 Electric displacement vector: D=?0E?P,
∇⋅D=?f , D=?0E.

介质中的高斯定理 Gauss' law in the presence of dielectrics: Flux of D out of a closed surface equals to total free charge enclosed within the surface. ∫SD⋅dS=∫V?fd?.

电场和电位移的边界条件 Boundary condition for E and D: E1||=E2||, D2⊥=D1⊥,
orD2⊥−D1⊥=?f.

存在电介质情形的能量 (Energy in the presence of dielectrics): U=12∫VD⋅Ed?