Vacuum Permittivity

Measures how easily electric fields permeate empty space, appearing in Coulomb's law as 1/4πε₀.

Specifications & Metrics

symbol

ε₀

status

Measured (CODATA 2022)

value

8.8541878188 × 10⁻¹² ± 1.4 × 10⁻²¹ F·m⁻¹

Relative Scale in Constants

Core Principles & Analysis

• Sets the strength of Coulomb's law: F = q₁q₂/4πε₀r².
• Exact by definition until 2019; now measured, with its uncertainty tracking the fine-structure constant's.
• Together with μ₀ it fixes the speed of light through ε₀μ₀c² = 1.

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