For an electromagnetic wave propagating in sodium, plot the real and imaginary part of the wave number k as a funciton of frequency (use a logarithmic scale) from 10^6 to 10^16 Hz.
Determine the penetration depth for 10^6, 10^15, and 2*10^15 Hz.
Conductivity of sodium is 5.32*10^-3 and the collisioni time is 2.98*10^-14 s.