permittivity

per·mit·tiv·i·ty

P0201700 (pûr′mĭ-tĭv′ĭ-tē)n. pl. per·mit·tiv·i·ties A measure of the ability of a material to interact with an electric field and become polarized by the field, so that the field within the material is weaker than the field in the absence of the material. The permittivity of a material is the product of the dielectric constant of the material and the permittivity of a perfect vacuum, which is defined to be about 8.854 × 10^-12 farad per meter.

permittivity

(ˌpɜːmɪˈtɪvɪtɪ) n, pl -ties (General Physics) a measure of the response of a substance to an electric field, expressed as the ratio of its electric displacement to the applied field strength; measured in farads per metre. Symbol: ε See also relative permittivity, electric constant

per•mit•tiv•i•ty

(ˌpɜr mɪˈtɪv ɪ ti)

n., pl. -ties. the ratio of the flux density produced by an electric field in a given dielectric to the flux density produced by that field in a vacuum. [1885–90]

Translations

permittivity

Permittivity

A property of a dielectric medium that determines the forces that electric charges placed in the medium exert on each other. If two charges of q₁ and q₂ coulombs in free space are separated by a distance r meters, the electrostatic force F newtons acting upon each of them is proportional to the product of the charges and inversely proportional to the square of the distance between them. Thus, F is given by Eq. (1), (1) where 1/(4&pgr;ε₀) is the constant of proportionality, having the magnitude and dimensions necessary to satisfy Eq. (1). This condition leads to a value for ε₀, termed the permittivity of free space, given by Eq. (2), where (2) c is the velocity of light in vacuum.

If now the charges are placed in a dielectric medium that is homogeneous and isotropic, the force on each of them is reduced by a factor ε_r, where ε_r is greater than 1. This dimensionless scalar quantity is termed the relative permittivity of the medium, and the product ε₀ε_r is termed the absolute permittivity ε of the medium.

A consequence is that if two equal charges of opposite sign are placed on two separate conductors, then the potential difference between the conductors will be reduced by a factor ε_r when the conductors are immersed in a dielectric medium compared to the potential difference when they are in vacuum. Hence a capacitor filled with a dielectric material has a capacitance ε_r times greater than a capacitor with the same electrodes in vacuum would have. Except for exceedingly high applied fields, unlikely normally to be reached, ε_r is independent of the magnitude of the applied electric field for all dielectric materials used in practice, excluding ferroelectrics. See Capacitance, Capacitor, Ferroelectrics

permittivity

[‚pər·mə′tiv·əd·ē] (electricity) The dielectric constant multiplied by the permittivity of empty space, where the permittivity of empty space (ε₀) is a constant appearing in Coulomb's law, having the value of 1 in centimeter-gram-second electrostatic units, and of 8.854 × 10^-12 farad/meter in rationalized meter-kilogram-second units. Symbolized ε.

单词	permittivity
释义	permittivity per·mit·tiv·i·ty P0201700 (pûr′mĭ-tĭv′ĭ-tē)n. pl. per·mit·tiv·i·ties A measure of the ability of a material to interact with an electric field and become polarized by the field, so that the field within the material is weaker than the field in the absence of the material. The permittivity of a material is the product of the dielectric constant of the material and the permittivity of a perfect vacuum, which is defined to be about 8.854 × 10^-12 farad per meter. permittivity (ˌpɜːmɪˈtɪvɪtɪ) n, pl -ties (General Physics) a measure of the response of a substance to an electric field, expressed as the ratio of its electric displacement to the applied field strength; measured in farads per metre. Symbol: ε See also relative permittivity, electric constant per•mit•tiv•i•ty (ˌpɜr mɪˈtɪv ɪ ti) n., pl. -ties. the ratio of the flux density produced by an electric field in a given dielectric to the flux density produced by that field in a vacuum. [1885–90] Translations permittivity Permittivity A property of a dielectric medium that determines the forces that electric charges placed in the medium exert on each other. If two charges of q₁ and q₂ coulombs in free space are separated by a distance r meters, the electrostatic force F newtons acting upon each of them is proportional to the product of the charges and inversely proportional to the square of the distance between them. Thus, F is given by Eq. (1), (1) where 1/(4&pgr;ε₀) is the constant of proportionality, having the magnitude and dimensions necessary to satisfy Eq. (1). This condition leads to a value for ε₀, termed the permittivity of free space, given by Eq. (2), where (2) c is the velocity of light in vacuum. If now the charges are placed in a dielectric medium that is homogeneous and isotropic, the force on each of them is reduced by a factor ε_r, where ε_r is greater than 1. This dimensionless scalar quantity is termed the relative permittivity of the medium, and the product ε₀ε_r is termed the absolute permittivity ε of the medium. A consequence is that if two equal charges of opposite sign are placed on two separate conductors, then the potential difference between the conductors will be reduced by a factor ε_r when the conductors are immersed in a dielectric medium compared to the potential difference when they are in vacuum. Hence a capacitor filled with a dielectric material has a capacitance ε_r times greater than a capacitor with the same electrodes in vacuum would have. Except for exceedingly high applied fields, unlikely normally to be reached, ε_r is independent of the magnitude of the applied electric field for all dielectric materials used in practice, excluding ferroelectrics. See Capacitance, Capacitor, Ferroelectrics permittivity [‚pər·mə′tiv·əd·ē] (electricity) The dielectric constant multiplied by the permittivity of empty space, where the permittivity of empty space (ε₀) is a constant appearing in Coulomb's law, having the value of 1 in centimeter-gram-second electrostatic units, and of 8.854 × 10^-12 farad/meter in rationalized meter-kilogram-second units. Symbolized ε.
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