2. Sample Papers
  3. NEET

NEET Sample Paper NEET Sample Test Paper-20

  • question_answer
    A liquid stands at the same level I arms A and B of a U-tube. If the U-tube is given a constant acceleration \[a(<g)\]towards the right as shown in the figure, the level of liquid in limb A rises to a height h above the level in limb B. If the length of the horizontal part of the U-tube is L, the value of h is given by

    A) \[\frac{La}{g}\]                                  

    B)  \[\frac{Lg}{a}\]                     

    C)      \[L\left( 1+\frac{a}{g} \right)\]          

    D)      \[L\left( 1-\frac{a}{g} \right)\] 

    Correct Answer: A

    Solution :

    Let \[{{P}_{1}}\]and\[{{P}_{2}}\] be the pressures at the bottom of limbs A and B, then \[{{P}_{1}}-{{P}_{2}}=h\rho g\] (\[\rho =\]density of liquid) If A is the cross-sectional area of the U-tube, the force at the horizontal part of the tube is \[F=({{P}_{1}}-{{P}_{2}})A=h\rho \,g\,A\]                                       (1) Now F = ma, where\[m=\rho AL\]is the mass of the liquid in length L. Hence \[F=\rho \,AL\,a\]                                               (2) Equating (1) and (2), we get \[h=\frac{La}{g}.\]So the correct choice is (a).                   Hence, the correction option is (a).


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