Q$3$ In a Kirkendall diffusion experiment analyzed by Matano method the following data are obtained at the

cross section containing the marker: Diffusion time $(t)=200$ hours, marker movement $(x)=1\mathrm{.}44mm$

interdiffusion co$-$efficient $(D^{-})={10}^{-11}{m}^{2}se{c}^{-1},$ slope of the penetration curve at the marker del$\frac{x_B}{d}$elx$=0\mathrm{.}2m{m}^{-1}$

and atomic fraction $A=0\mathrm{.}4.$ Compute the intrinsic diffusivities of A and B $.$