JEE Main & Advanced Physics Fluid Mechanics, Surface Tension & Viscosity / द्रव यांत्रिकी, भूतल तनाव और चिपचिपापन Question Bank Mock Test - Mechanical Properties of Fluids

  • question_answer
    A large open tank has two holes in the wall. One is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth 4y from the top. When the tank is completely filled with water, the quantities of water flowing out per second from both the hole are the same. Then R is equal to

    A) \[2\pi L\]          

    B) \[\frac{L}{\sqrt{2\pi }}\]

    C) \[L\]                

    D) \[\frac{L}{2\pi }\]

    Correct Answer: B

    Solution :

    [b] Velocity of efflux when the hole is at depth h. \[v=\sqrt{2gh}\] Rate of flow of water form square hole \[{{Q}_{1}}={{a}_{1}}{{v}_{1}}={{L}^{2}}\sqrt{2gy}\] Rate of flow of water from circular hole \[{{Q}_{2}}={{a}_{2}}{{v}_{2}}=\pi {{R}^{2}}\sqrt{2g(4y)}\] According to problem, \[{{Q}_{1}}={{Q}_{2}}\] \[\Rightarrow {{L}^{2}}\sqrt{2gy}=\pi {{R}^{2}}\sqrt{2g(4y)}\Rightarrow R=\frac{L}{\sqrt{2\pi }}\]


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