In Maxwell's correction to Ampère's law, this quantity multiplies the time derivative of E but  not  J, since, without polarization, it is the ratio between the displacement and electric fields.
Surface plasmon resonance requires an interface across which this quantity changes sign, like a sheet of gold. In SI units, the reciprocal of this quantity is defined as the speed of light squared, times four pi, divided by ten million. In Maxwell's correction to Ampère's law, this quantity multiplies the time derivative of E but  not  J, since, without polarization, it is the ratio between the displacement and electric fields. The capacitance of parallel plates depends on the plates' (*)  area, their separation distance, the dielectric constant, and this quantity. The flux through a Gaussian surface equals the enclosed charge over this quantity. Coulomb's constant equals one over four pi times this constant's value in a vacuum. For 10 points, name this quantity symbolized epsilon.
Surface plasmon resonance requires an interface across which this quantity changes sign, like a sheet of gold.
electric  permittivity  [or  permittivity  of free space; or vacuum  permittivity ; or  epsilon  or epsilon -naught until it is read]