Question

A manometer connected to a closed tap reads 4.5 $\times$ ${10}^5$ pascal. When the tap is opened, the reading of the manometer falls to 4 $\times$ ${10}^5$ pascal. Then the velocity of flow of water is

• A. 7 m $s^{-1}$
• B. 8 m $s^{-1}$
• C. 9 m $s^{-1}$
• D. 10 m $s^{-1}$

Answer 1

The correct option is D 10 m $s^{-1}$

The velocity of the flow of water is given by

$\frac{P_1-P_2}{\rho g}$$=\frac{v^2}{2g}\Rightarrow \frac{4.5\times {10}^5-4\times {10}^5}{{10}^3\times g}$

$=\frac{v^2}{2g}\therefore v=10m/s$