Response of electron gas it is sometimes stated erroneously in books on electromagnetism that the static conductivity , which in Gaussian units has the dimensions

Response of electron gas it is sometimes stated erroneously in books on electromagnetism that the static conductivity σ, which in Gaussian units has the dimensions of a frequency, measures the response frequency of a metal to an electric field suddenly applied. Criticize this statement as it might apply to copper at room temperature. The resistivity is –1μohm-cm; the electron concentration is 8 x 10²² cm^–3; the mean free path is – 400A; the Fermi velocity is 1.6 x 10⁸ cm s ^–1. You will not necessarily need all these data. Give the order of magnitude of the three frequencies σ, w_p, and 1/τ that might bc relevant in the problem. Set up and solve the problem of the response x (t) of the system to an electric field E(t < 0) = 0; E(t > 0) = I. The system is a sheet of copper; the field is applied normal to the sheet. Include the damping. Solve the differential equation by elementary methods.