Most materials {insulator}| {dielectric} allow no free electron movement. Air, vacuum, paper, and glass are insulators.
dipoles
Outside electric field separates electrons and protons, to make induced charge. Inducing charge can be easy or hard. Dielectric strength is ratio between material capacitance and vacuum capacitance. For vacuum, dielectric constant is 1. For insulators, dielectric constant is 1 to 8. For water, dielectric constant is 81, because water has high polarization and free dipole rotation. For conductors, dielectric constant is infinite. Lustrous metals have negative dielectric constant.
Materials have ease by which electric fields can go through {permittivity}|. Metals have free electrons and cannot have electric fields inside. Insulators have charges that move relative to electric field and oppose electric field. Empty space has no charges and allows electric field. Electric-force constant k inversely depends on permittivity.
Insulators have different abilities to make dipoles {polarizability}| {polarization, electricity}. If polarization is more, refraction index is more. Polarization K is refractive index n squared: K = n^2. Metal has free electrons and cannot make dipoles. Empty space has no charges and cannot make dipoles.
5-Physics-Electromagnetism-Conductivity
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Date Modified: 2022.0225