JEE Main & Advanced Physics Fluid Mechanics, Surface Tension & Viscosity / द्रव यांत्रिकी, भूतल तनाव और चिपचिपापन JEE PYQ-Fluid Mechanics, Surface Tension and Viscosity

  • question_answer
    Water from a pipe is coming at a rate of 100 litres per minute. If the radius of the pipe is 5 cm, the Reynolds number for the flow is of the order of : (density of water \[=1000kg/{{m}^{3}},\]coefficient of viscosity of water = 1mPas) [JEE Main 8-4-2019 Morning]

    A) \[{{10}^{6}}\]            

    B)      \[{{10}^{3}}\]

    C) \[{{10}^{4}}\]            

    D)      \[{{10}^{2}}\]

    Correct Answer: C

    Solution :

    [c] Reynolds Number\[=\frac{\rho \text{v}d}{\eta }\]
    Volume flow rate \[=\text{v}\times \pi {{r}^{2}}\]
    \[\text{v}=\frac{100\times {{10}^{-3}}}{60}\times \frac{1}{\pi \times 25\times {{10}^{-4}}}\]
    \[\text{v}=\frac{2}{3\pi }m/s\]
    Reynolds Number\[=\frac{{{10}^{3}}\times 2\times 10\times {{10}^{-2}}}{{{10}^{-3}}\times 3\pi }\]
    \[\simeq 2\times {{10}^{4}}\]
    order\[{{10}^{4}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner