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

  • question_answer
    If the excess pressure inside a soap bubble is balanced by oil column of height 2 mm, then the surface tension of soap solution will be (r = 1 cm and density d = 0.8 gm/cc)        [J & K CET 2004]

    A) 3.9 N/m

    B)                      \[3.9\text{ }\times {{10}^{2}}N/m\]

    C)             \[3.9\text{ }\times {{10}^{3}}N/m\]

    D) 3.9 dyne/m

    Correct Answer: B

    Solution :

                    \[\frac{4T}{R}=hdg\]\ \[\]\[T=\frac{Rhdg}{4}\] T \[=\frac{{{10}^{-2}}\times 2\times {{10}^{-3}}\times 0.8\times {{10}^{3}}\times 9.8}{4}\]\[=3.9\times {{10}^{-2}}\,N/m\]


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