JEE Main & Advanced Physics Fluid Mechanics, Surface Tension & Viscosity / द्रव यांत्रिकी, भूतल तनाव और चिपचिपापन Question Bank Pressure and Density

  • question_answer
    If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake [RPET 2000]

    A)            10 m                                        

    B)            20 m                                        

    C)            60 m                                        

    D)            30 m

    Correct Answer: B

    Solution :

                       Pressure at bottom of the lake = \[{{P}_{0}}+h\rho g\]                    Pressure at half the depth of a lake \[={{P}_{0}}+\frac{h}{2}\rho g\]                    According to given condition                    \[{{P}_{0}}+\frac{1}{2}h\rho g=\frac{2}{3}({{P}_{0}}+h\rho g)\] Þ \[\frac{1}{3}{{P}_{0}}=\frac{1}{6}h\rho g\]             Þ  \[h=\frac{2{{P}_{0}}}{\rho g}=\frac{2\times {{10}^{5}}}{{{10}^{3}}\times 10}=20m\].


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