Q178 / 180 · KCET 2024 · Physics
Water flows through a horizontal pipe of varying cross-section at a rate of $0.314 \mathrm{~m}^3 \mathrm{~s}^{-1}$. The velocity of water at a point where the radius of the pipe is 10 cm is
- A$0.1 \mathrm{~ms}^{-1}$
- B$1 \mathrm{~ms}^{-1}$
- Correct answerC$10 \mathrm{~ms}^{-1}$
- D$100 \mathrm{~ms}^{-1}$
Solution
Given, flow rate, $Q=0.314 \mathrm{~m}^3 \mathrm{~s}^{-1}$
$r=10 \mathrm{~cm}=0.1 \mathrm{~m}$
$=10^{-1} \mathrm{~m}$
Since, $\quad Q=A v$
$0.314=\pi r^2 v$
$0.314=314 \times 10^{-2} v$
$\Rightarrow \quad v=10 \mathrm{~m} / \mathrm{s}$
Hence, the correct answer is option: 'C'.