Question

Define the dielectric constant of a medium. What is its SI unit?

Answer 1

Permittivity:

1. Permittivity, also known as electric permittivity, is a proportionality constant found between electric displacement and electric field intensity.
2. In free space, this constant is approximately $8.85\times {10}^{-12}$ farad per meter (F/m) (a vacuum).

Dielectric constant:

1. The dielectric constant of a substance is defined as the ratio of the substance's permittivity to the permittivity of free space.
2. It can be written as $K=\frac{\epsilon }{{\epsilon }_o}$.
3. It is a unitless, dimensionless quantity because it is the ratio of two like entities.