Permittivity
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Permittivity is a fundamental physical quantity that describes how an electric field affects, and is affected by, a dielectric medium. It is a measure of the ability of a material to store electrical energy in an electric field. The permittivity of a material determines how much electric field (or electric flux) is 'permitted' to pass through the material.
Definition[edit | edit source]
Permittivity is denoted by the symbol ε. The SI unit for permittivity is the farad per meter (F/m). The permittivity of free space, also known as the vacuum permittivity, is a physical constant denoted by ε₀. The relative permittivity, also known as the dielectric constant, is the ratio of the permittivity of a material to the permittivity of free space.
Mathematical Expression[edit | edit source]
The permittivity ε of a material can be expressed as: \[ \varepsilon = \varepsilon_0 \varepsilon_r \] where:
- \(\varepsilon_0\) is the vacuum permittivity (approximately \(8.854 \times 10^{-12} \, \text{F/m}\))
- \(\varepsilon_r\) is the relative permittivity of the material
Vacuum Permittivity[edit | edit source]
The vacuum permittivity, ε₀, is a fundamental physical constant that characterizes the permittivity of free space. It is a key parameter in Maxwell's equations and plays a crucial role in the propagation of electromagnetic waves.
Relative Permittivity[edit | edit source]
The relative permittivity, εᵣ, also known as the dielectric constant, is a dimensionless quantity that describes how much a material can polarize in response to an electric field, relative to the vacuum. It is given by: \[ \varepsilon_r = \frac{\varepsilon}{\varepsilon_0} \]
Applications[edit | edit source]
Permittivity is a critical parameter in various fields of physics and engineering, including:
See Also[edit | edit source]
References[edit | edit source]
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