Electric permittivity of vacuum

Above, So is the electric permittivity of vacuum and, similarly, is the magnetic permeability of vacuum. 

Here, qi is a charge in distribution, qj is a charge in distribution B, and r,j is the separation between charges qt and qj. Quantity % is the electric permittivity of vacuum, a physical constant equal to 8.854 19 x 10" C V m . (The unit of electric charge is the coulomb C, and tire unit of electric potential difference is the volt V.) The sums are taken over all charges in tire distributions. 

Here eo is electric permittivity of vacuum, P is the dielectric polarization density,... 

In other words, the product of the electric permittivity of vacuum and the permeability of vacuum is the square of the velocity of light. The permeability is related to magnetism and has the units of m kg s A . It is magnetic induction per length. Thus, the electric permittivity has the units of m kg s A. It is an electrical capacity per length. From these considerations, the electric susceptibiUty turns out as a dimensionless quantity. 

Table 8-2 lists several physical properties pertinent to our concern with the effects of solvents on rates for 40 common solvents. The dielectric constant e is a measure of the ability of the solvent to separate charges it is defined as the ratio of the electric permittivity of the solvent to the permittivity of the vacuum. (Because physicists use the symbol e for permittivity, some authors use D for dielectric constant.) Evidently e is dimensionless. The dielectric constant is the property most often associated with the polarity of a solvent in Table 8-2 the solvents are listed in order of increasing dielectric constant, and it is evident that, with a few exceptions, this ranking accords fairly well with chemical intuition. The dielectric constant is a bulk property. 

In isotropic media 0 and S are related by = < , where the scalar parameter a is now referred to as the permittivity. In the international (SI) system it is given by s = erso. where o is the permittivity of vacuum (see Appendix fl) and e, is a dimensionless permittivity that characterizes the medium. Furthermore, according to Ohm s law the current is given by 7 = cr< , where a is the electrical conductivity. The relation V S3 = 0 is a mathematical statement of the observation that isolated magnetic poles do not exist. 

Debye-Huckel parameter. (V2 Laplace operator, o -> permittivity of vacuum, er -> dielectric constant of the electrolyte solution, cf bulk concentrations of all ions i, zp charges of the ions i, f electric potential, k - Boltzmann constant, and T the absolute temperature). See also -5- Debye-Huckel theory. 

Here v is the velocity of the particle, E is the electric field strength, eo is the - permittivity of vacuum, eT is the dielectric constant of the electrolyte solution, ( is the equilibrium potential at the plane of shear (- zeta potential), and tj is the -> viscosity. See also -> Smolu-chowski equation (for the case of xr 1). 

The induced dipole moment is defined as = 47t eq oc E (eq permittivity of vacuum a electric polarizability of the molecule E electric field strength). 

Here, a is the charge of the wire per unit length and eo is the electric permittivity of the vacuum (eo = 8.85 x 10 C /Nm ). Superposing the fields of the two oppositely charged wires, we obtain the following expression for the electric field on the x axis... 

Dielectric Ellipsoid. The general formulae (328) and (336) permit the calculation of electrostrictive and electrocaloric changes in electric permittivity of a dielectric of arbitrary geometrical shape. To this aim, one has only to resort to the relation between the macroscopic field E existing in the anisotropic dielectric and the electric field in vacuum ... 

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