Dielectrics 10 20 14 9 19 AM Don t conduct but not called an insulator because there is no such thing as a perfect insulator dielectrics are in between insulators and conductors Conductor Dielectrics the object is responding to the electric field with motion but a small amount Dielectrics respond to external fields Orientation of permanent dipoles in polar molecules o Polar molecules have a charge permanently attached to them o o The particles won t all move perfectly in line with the electric field but most of them will be somewhat lines up to face in the direction of the field Net dipole moment p net Polarization of non polar molecules direction o absolute value of electric field due to electrons b c we know Dipole moment is induced and is proportional to the external electric field by the proportionality constant alpha which is the polarizability polarization o It fights the external electric field Induced dipoles set up an internal field in dielectric properties o o Example o You will have some negative on the bottom and some positive on the top because the internal charges cancel except for the ones on the edges so Large ke implies high degree polarization Air ke 1 0006 Paper ke 3 5 Water ke 80 The more water in the air the more you reduce the field which explains why you generally don t get shocked on a humid day In a dielectric the charges are bound Gauss Law inside dielectrics Electric field generated by two plates conducting This is true by accounting for bound charges But also can If electric field inside a medium that is lower than outside then the capacitance changes Inside a dielectric o C ke C0 C0 capacitance inside a vacuum ke the same ke as above the dielectric constant Capacitance increases when you introduce a dielectric for a constant size if you change the medium you can store more energy In a dielectric media o IMPORTANT NOTE
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