What is permittivity in an intuitive manner ? Like is permittivity related to the resistance against charge flow ? or is permittivity related to how easily electric field lines can pass through it ?

And if it is related to how easily field lines pass,and if high permittivity means that electric filed lines can easily pass through the medium, then why is F=1/4PI.Q1Q2/R^2 ?


  • $\begingroup$ What do you not like about the definition in e.g. en.wikipedia.org/wiki/Permittivity? If you don't like "polarizability" because "polarization of the physical vacuum" is a bit suspect, then you can use the electrostatic energy density formula: u_e=E^2/(2*epsilon_0). We observe that the field between two capacitor plates can store that much energy per volume and define the permittivity as the necessary proportionality constant (for whatever units for energy, volume and electric field we are using). epsilon_r for materials then becomes a relative measure for matter compared to vacuum. $\endgroup$ Apr 25, 2023 at 18:21
  • $\begingroup$ So does it mean it is the factor of the medium depending upon the amount of electric field (not sure if it is amount) or electric energy that can be stored in the medium between two capacitor plates ( is it something like resistance ? ) I apologize for my overbearing ignorance. $\endgroup$ Apr 25, 2023 at 18:50
  • $\begingroup$ Yes. If we fill matter inside a plate capacitor, then the polarizability of the matter will increase the total stored energy. The increase relative to the vacuum is the relative permittivity epsilon_r. The response of a dielectric material to an external field is a polarization which reduces the external field, so in a way the material "resists" the external field, similar to how a spring would resist an external force pulling on it, but not in the way that an electrical resistance will convert electric current to heat. And just like a spring a dielectric stores energy by doing that. $\endgroup$ Apr 25, 2023 at 19:03
  • $\begingroup$ Thank you so much $\endgroup$ Apr 26, 2023 at 10:29


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