Determine the k = 0 plasmon frequency for a gas of electrons with mass equal to the free electron mass, in a system with low-frequency dielectric constant ϵ = 2ϵ₀, and density 10¹⁹ cm⁻³. A convenient unit conversion is e²/4πϵ₀ = 1.44 × 10⁻⁷ eV-cm.