Check out the complete information about Epsilon Naught Value like meaning, unit, formula, FAQs etc. Epsilon naught (& epsilon ;o) is the permittivity of free space that determines the electric field strength in vacuum. Learn how to calculate its value , units, dimensions and applications in physics, and the difference between absolute and relative permittivity. CONCEPT: The permittivity of free space represents the capability of a vacuum to permit electric fields. The SI unit of permittivity of free space is m -3 Kg -1 s 4 A 2 and is given by ϵ 0 = 8.85 × 10 12 m 3 K g 1 s 4 A 2 The permeability of free space is the ability of free space to get magnetized with respect to the externally applied field or else it represents the extent to magnetic field lines can enter substance. The SI unit of permeability of free space is H/m or TmA-1 μ 0 = 4 π ... In every location in the cosmos, the Epsilon Naught value remains constant. Vacuum permittivity is represented by ε0, which is pronounced as either Epsilon Naught or Epsilon Zero.