The constitutive parameters of copper are = 0 = 4 10-7 (H / m),

The constitutive parameters of copper are μ = μ0 = 4π × 10-7 (H / m), ε = ε0 ~ (1 / 36π) × 10-9 (F / m), and σ = 5.8 × 107 (S / m). Assuming that these parameters are frequency independent, over what frequency range of the electromagnetic spectrum is copper a good conductor?