Question

Are dielectric permittivity and dielectric constant the same?

Answer 1

No, dielectric permittivity and dielectric constant are related but not exactly the same.

1. Dielectric Permittivity (\(\varepsilon\)):  
   

   This is a material property that indicates how much electric field is reduced within a material when it's placed in an electric field. It represents the ability of a material to permit the electric field to pass through it. It is usually expressed as \(\varepsilon = \varepsilon_0 \varepsilon_r\), where:
   - \(\varepsilon_0\) is the permittivity of free space (a constant, approximately \(8.85 \times 10^{-12} \, \text{F/m}\)),
   - \(\varepsilon_r\) is the relative permittivity (also called the dielectric constant).

1. Dielectric Constant (\(\varepsilon_r\)):  
   

   This is the ratio of the permittivity of a material to the permittivity of free space. It is a dimensionless number and gives a measure of how much the material can polarize in response to an electric field. In simple terms, it tells you how much more the material can store electrical energy compared to a vacuum.

In Summary:

1. Dielectric permittivity is a broader term, including both the material's inherent properties and the vacuum's properties.
   

1. Dielectric constant is specifically the relative permittivity (\(\varepsilon_r\)) of a material compared to a vacuum.
   

So, they are closely related, but not the same thing!