A light beam containing red and violet wavelengths is incident on a slab of quartz at an angle of incidence of $50.0^{\circ}$. The index of refraction of quartz is 1.455 at $600 \mathrm{nm}$ (red light), and its index of refraction is 1.468 at $410 \mathrm{nm}$ (violet light). Find the dispersion of the slab, which is defined as the difference in the angles of refraction for the two wavelengths.