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31-05-2021 Dielectric Constant

Q. Why is dielectric constant important?


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Dapzoi Verified
Commented on 2021-05-31 16:54:33 (IST)
Dielectric Constant : The dielectric constant of a material, also called the permittivity of a material, represents the ability of a material to concentrate electrostatic lines of flux. In more practical terms, it represents the ability of a material to store electrical energy in the presence of an electric field. All materials, including vacuum, store energy when placed in an electric field. The permittivity of vacuum is defined as the physical constant ε0, which is approximately ε0 = 8.854 x 10-12 farads per meter. This constant appears in many electromagnetism formulas.

Since most capacitors are not made of vacuum, it makes sense to define permittivity for every material. The permittivity of a material is defined ε=εrε0, where ε is the absolute permittivity and εr is the relative permittivity. εr is a number which is always greater than 1, meaning that all materials store more energy than free space when subjected to an electric field. This property is quite useful in capacitor applications, and we will explain this further in this article. It should be noted that the relative permittivity depends on many factors, such as temperature, pressure and even frequency, which is why materials with more stable dielectric constant are favored in some applications.