Epsilon naught, denoted as ε0, is a fundamental physical constant in electromagnetism known as the permittivity of free space.
The value of epsilon naught is approximately 8.854 x 10-12 F/m (farads per meter). This constant plays a crucial role in the formulation of Coulomb’s law, which describes the force between two point charges, and it appears in equations related to electric fields and capacitance.
To put it simply, epsilon naught measures how much electric field is ‘allowed’ to exist in a vacuum. It essentially describes how much charge can be stored in a capacitor for a given electric field strength. The higher the value of epsilon naught, the more capacitance a material will provide, which is important for designing various electrical components.