What does ε0 represent in electromagnetism?

What does ε0 represent in electromagnetism?

• A. Permeability of free space
• B. Permittivity of free space
• C. Electrical conductivity of air
• D. Electrical resistance of vacuum

Answer: (B)

ε0 is the permittivity of free space, the constant that sets how electric fields behave in vacuum. It tells you how much electric field is produced by a given charge in empty space and appears directly in Coulomb’s law through the factor 1/(4π ε0), which governs the strength of electrostatic forces between charges. In vacuum, the electric displacement D relates to the electric field E by D = ε0 E, so ε0 links the field to how the space responds to it. This constant also connects electric and magnetic phenomena: the speed of light c satisfies c^2 = 1/(μ0 ε0), tying ε0 to μ0, the permeability of free space, and showing how electromagnetic waves propagate in vacuum. The value is about 8.854 × 10^-12 farads per meter (F/m). The other options describe different concepts: permeability of free space is μ0, not ε0; electrical conductivity of air is a material property that varies with conditions; and electrical resistance of vacuum isn’t a standard constant (the relevant vacuum property is the impedance of free space, Z0, not a resistance).

ε0 is the permittivity of free space, the constant that sets how electric fields behave in vacuum. It tells you how much electric field is produced by a given charge in empty space and appears directly in Coulomb’s law through the factor 1/(4π ε0), which governs the strength of electrostatic forces between charges. In vacuum, the electric displacement D relates to the electric field E by D = ε0 E, so ε0 links the field to how the space responds to it.

This constant also connects electric and magnetic phenomena: the speed of light c satisfies c^2 = 1/(μ0 ε0), tying ε0 to μ0, the permeability of free space, and showing how electromagnetic waves propagate in vacuum. The value is about 8.854 × 10^-12 farads per meter (F/m).

The other options describe different concepts: permeability of free space is μ0, not ε0; electrical conductivity of air is a material property that varies with conditions; and electrical resistance of vacuum isn’t a standard constant (the relevant vacuum property is the impedance of free space, Z0, not a resistance).