Question 115: Properties of Matter

Question

An air bubble of negligible weight having radius r rises steadily through a solution of density $$\sigma$$ at speed v. The coefficient of viscosity of the solution is given by :

Accepted Answer

Air bubble moves with constant speed v. So net force = 0.
$$	herefore$$ Buoyant Force = Viscous force
$$ \Rightarrow {F_b} = {F_v}$$
$$ \Rightarrow \sigma  	imes {4 \over 3}\pi {r^3}g = 6\pi nrv$$
$$ \Rightarrow n = {{2\sigma {r^2}g} \over {9v}}$$

Answer

$$\eta  = {{4r\sigma g} \over {9v}}$$

Answer

$$\eta  = {{2{r^2}\sigma g} \over {9v}}$$

Answer

$$\eta  = {{2\pi {r^2}\sigma g} \over {9v}}$$

Answer

$$\eta  = {{2{r^2}\sigma g} \over {3\pi v}}$$

Properties of Matter

An air bubble of negligible weight having radius r rises steadily through a solution of density $\sigma$ at speed v. The coefficient of viscosity of the solution is given by :

Choose the correct answer: