Show that for high frequencies (ω ≫ ν) the dielectric constant (as derived in Problem 7.8)...

Show that for high frequencies (ω ≫ ν) the dielectric constant (as derived in Problem 7.8) is essentially real with frequency dependence of the form

where is known as the plasma frequency. The above dielectric constant variation is indeed valid for X-ray wavelengths in many metals. Assuming that at such frequencies all the electrons an be assumed to be free, calculate ωp for copper for which the atomic number is 29, mass number is 63 and density is 9 g/cm3.

        [Ans: ~ 9 × 10 16 sec – 1]