PhysicsEasy148×since 2002Q7914An air bubble of negligible weight having radius r rises steadily through a solution of density σ\sigmaσ at speed v. The coefficient of viscosity of the solution is given by :Aη=4rσg9v\eta = {{4r\sigma g} \over {9v}}η=9v4rσgBη=2r2σg9v\eta = {{2{r^2}\sigma g} \over {9v}}η=9v2r2σgCη=2πr2σg9v\eta = {{2\pi {r^2}\sigma g} \over {9v}}η=9v2πr2σgDη=2r2σg3πv\eta = {{2{r^2}\sigma g} \over {3\pi v}}η=3πv2r2σgCheck answerSkip