Question

At what speed, the velocity head of water is equal to pressure head of $40cm$ of mercury?

• A. 2.8 m / s
• B. 10.32 m / s
• C. 5.6 m / s
• D. 8.4 m / s

Answer 1

Answer: (B)

$\frac{1}{2}{\rho }_{\text{water }}{V}^2={\rho }_{\text{mercury }}gh$
$V=\sqrt{2\times \frac{{\rho }_{\text{mercury}}}{{\rho }_{\text{water }}}\times g\times h}$
$=\sqrt{2\times 13.6\times 9.8\times \frac{40}{100}}$
$\Rightarrow V=10.32m/s$