Water coming out of the mouth of a tap and falling vertically in streamline flow forms a tapering column, i.e., the area of cross-section of the liquid column decreases as it moves down. Which of the following is the most accurate explanation for this
  • A
    As the water moves down, its speed increases and hence its pressure decreases. It is then compressed by the atmosphere
  • B
    Falling water tries to reach a terminal velocity and hence reduces the area of cross-section to balance upward and downward forces
  • CThe mass of water flowing past any cross-section must remain constant. Also, water is almost incompressible. Hence, the rate of volume flow must remain constant. As this is equal to velocity $×$ area, the area decreases as velocity increases
  • D
    The surface tension causes the exposed surface area of the liquid to decrease continuously
Medium
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