If the intrinsic diffusivity of component A is larger than that of component B, in which direction will there be a net drift of vacancies in a diffusion couple? Will there be consequences of the unequal intrinsic diffusivities in a diffusion experiment? Why is this problematic for the alloy sample? (An example is a diffusion couple consisting of pure Cu and Cu - 30% Zn.) Show qualitatively (by plotting schematically) how the position of markers changes in time.