PHYS 230 Lecture Notes - Lecture 3: Energy Density, Relative Permittivity, Wax Paper
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Related reading: lea text book, chapter 27. 2, 27. 3, 27. 4. 1. Note that resistance and capacitance add in opposite manner when combined (in series or in parallel). In series: in parallel voltage is the same in parallel. A dielectric is a non-conductor or insulator examples: rubber, glass, waxed paper. When placed in a charged capacitor, the dielectric reduces the potential difference between the two plates, when the plates are disconnected from batteries. Dielectric filling will increase capacitance by a factor of , hence, if free charge q is unchanged (disconnected to batteries etc), e field and v will reduce by a factor of. U reduce by a factor of if v is constant (connected to battery), q increases by a factor of , u increases by a factor of . In vacuum, energy density (energy per unit volume) of e field is. In dielectric, energy density (energy per unit volume) of e field is.
