Helium and nitrogen gas are contained in a conduit $10$ mm in diameter and $0\mathrm{.}1$ m long at $298$ K and a uniform constant pressure of $1\mathrm{.}0$ atm abs$.$ The partial pressure of He at one end of the tube is $0\mathrm{.}060$ atm and $0\mathrm{.}020$ atm at the other end. The diffusivity can be obtained D$=0\mathrm{.}6871042/.$ Calculate the following for the steady$-$state equimolar counter diffusion.

a$.$ Flux of He in kgmol$/$sm$2$

b$.$ Flux of N$2$ in kgmol$/$sm$2$