Answer Happy

Consider an electromagnetic wave in a conducting medium. a) Show that the penetration depth in a bad conductor (o << we) is (2/0) Velu (that is, independent of frequency). Find the penetration depth in meters for pure water. b) Show that the penetration depth in a good conductor (o >> we) is 1/21 (where 1 is the wavelength inside the conductor). Find the penetration depth (in nanometers) for a typical metal (o ~ 10+(12-m)-1) in the visible spectrum w = 1015/s, assuming e ~ €0 and u z Mo . Why are metals opaque? c) Show that in a good conductor the magnetic field lags 45° with respect to the electric field, and find the ratio of their amplitudes. For a numerical example consider a "typical metal” as described in the previous item.