Question

Is it correct to say that the polarization of an insulator is zero when no external electrical field is applied on the material?

Answer 1

Yes,the polarization of an insulator is zero,when no external electric field is applied on the material.

In insulators the electrons remain attached to individual atoms or molecules. Because the insulators have no free electrons in their excited states.Hence polarization is also zero when no external electric field is applied on the material.

However,the electrons can suffer small movements within the atoms or molecules under the influence of an external electric field.In view of these electrical properties insulators are called dielectrics.