Question

The flow rate of water from a tap of diameter $1.25cm$ is $3L$ per min. The coefficient of viscosity of water is $10^{-3}$ Pa s. The nature of the flow is

• A. Unsteady
• B. Turbulent
• C. Laminar
• D. None of these

Answer 1

Answer: (B)

Here, diameter of the tap,
$D=1.25cm=1.25\times 10^{-2}m$
Density of water, $\rho =10^{3}kg{m}^{-3}$
Coefficient of viscosity, $\eta =10^{-3}Pas$
Volume of water flowing out per second is
$Q=3Lpermin=\frac{3\times 10^{-3}{m}^3}{60S}=5\times 10^{-5}{m}^3{s}^{-1}$
Reynolds number is given by
$R_e=\frac{4\rho Q}{\pi D\eta }=\frac{4\times 10^{3}kg{m}^{-3}\times 5\times 10^{-5}{m}^3{s}^{-1}}{3.14\times 1.25\times 10^{-2}m\times 10^{-3}pas}$
$=5095>2000$
Thus, the flow will be turbulent