Problem 5.203

Assuming electrons of substance to be free when subjected to hard X-rays, determine by what magnitude the refractive index of graphite differs from unity in the case of X-rays whose wavelength in vacuum is equal to $\lambda=50 \mathrm{pm}$ .

Reveal Answer

n-1=-n_{0} e^{2} \lambda^{2} / 8 \pi^{2} \varepsilon_{0} m c^{2}=-5.4 \cdot 10^{-7}, \text {where } n_{0} \text { is the concentration of electrons in carbon}

Dispersion and Absorption of Light