The diameter of an air bubble which was initially 2 mm, rises steadily through a solution of density 1750 kg m^-3 at the rate of 0.35 cms^-1. The…

The diameter of an air bubble which was initially $\displaystyle 2$ mm, rises steadily through a solution of density $\displaystyle 1750 \mathrm{~kg} \mathrm{~m}^{-3}$ at the rate of $\displaystyle 0.35 \mathrm{cms}^{-1}$. The coefficient of viscosity of the solution is \_\_\_\_ poise (in nearest integer). (the density of air is negligible).