If an air bubble of diameter 2 mm rises steadily through a liquid of density 2000 kg / m^3 at a rate of 0.5 cm/s, then the coefficient of viscosity…

If an air bubble of diameter $\displaystyle 2$ mm rises steadily through a liquid of density $\displaystyle 2000 \mathrm{~kg} / \mathrm{m}^3$ at a rate of $\displaystyle 0.5$ cm/s, then the coefficient of viscosity of liquid is $\displaystyle \_\_\_\_$ Poise. (Take $\displaystyle \mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )