The Effect of Dielectric on Electric Displacement Vector

Under general conditions, electric displacement vector is not only related to free charges but also to polarized electric charges. The conditions where it is only related to free charges are given in this paper with investigations made into the distribution of polarized electric charges. It is concluded that when the dielectric is even, there emerge polarized electric charges only when there is distribution of free charges; polarized electric charges must emerge when the media are not even in the direction of electric field. However, no polarized electric charges emerge when the media are not even in vertical electric field.