MCQ
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
    $7 ms ^{-1}$
  • B
    $8 ms ^{-1}$
  • C
    $9 ms ^{-1}$
  • $10 ms ^{-1}$

Answer

Correct option: D.
$10 ms ^{-1}$
(d) $\frac{P_1-P_2}{\rho g}=\frac{v^2}{2 g} \Rightarrow \frac{4.5 \times 10^5-4 \times 10^5}{10^3 \times g}=\frac{v^2}{2 g} \therefore v=10 \mathrm{~m} / \mathrm{s}$

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