PHYS 142 Lecture Notes - Lecture 25: Relative Permittivity, Conservative Force, Dielectric
12 Mar 2015
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Phys 142: electromagnetism and optics - lecture 25: midterm correction session with the ta. Both the gravitational and the electrical forces follow a 1/r2 law because they were both determined as such by experimental measurements and not because they originate from the same fundamental theorem. In electricity, the analogue of gravitational potential energy is the electrical potential energy (joules), not the electric potential (volt) The main differences between gravitational and electrostatic interactions are: The electrostatic force can be either attractive or repulsive. The electrostatic force is stronger than gravitational force at very small scales or distances. Inside an ideal and infinite capacitor formed by two metallic plates, the electric field is constant inside the capacitor. The main effects of introducing a dielectric material with dielectric constant e>1 is to: Decrease the voltage drop between the metallic plates. Generate a polarization electric field that is opposite to the one with only vacuum.
