First page Back Continue Last page Overview Image
- PHY102 Physics II © Dr.Cem Özdoğan
- Polar dielectrics. The molecules of some dielectrics, like water, have permanent electric dipole moments.
- In such materials (called polar dielectrics), the electric dipoles tend to line up with an external electric field as in Figure.
- Since the molecules are continuously push&pull each other as a result of their random thermal motion, this alignment is not complete, but it becomes more complete as the magnitude of the applied field is increased.
- The alignment of the electric dipoles produces an electric field that is directed opposite the applied field and is smaller in magnitude.
- (a) Molecules with a permanent electric dipole moment, showing their random orientation in the absence of an external electric field.
- (b) An electric field is applied, producing partial alignment of the dipoles. Thermal agitation prevents complete alignment.
- 25-6 Capacitor with a Dielectric FYI