A $25$ mm diameter naphtalene sphere is held in an air stream at $1$ atm and $100$C$.$ At this temperature the vapor pressure of naphtalene is $20$ mmHg and $D_{AB}=8\mathrm{.}93*{10}^{-6}.$ Mass transfer coefficient was experimentally determined as $k_g=2\mathrm{.}5*{10}^{-3}$mol$/m^2.$s$.$atm. Calculate the mass transfer flux and effective film thickness according to the film theory.