Three identical vessels A, B and C are filled with water, mercury and kerosene respectively up to an equal height. The three vessels are provided with identical taps at the bottom of the vessels. If the three taps are opened simultaneously, then which vessel is emptied first? 2007)
✓ Correct answer: d) Vessel C
ExplanationThe time taken to empty a vessel depends on the flow rate of liquid through the tap.The flow rate is determined by Torricelli’s theorem, which states: v = √2gh, where; v is the velocity of liquid exiting the tap, g is the acceleration due to the gravity h is the height of the liquid column above the tap (identical for all vessels).Water, Kerosene and Mercury have different densities, but we can see that velocity is independent of the densities of the liquid.Viscosity (resistance to flow) affects the ease with which the liquid flows through the tap.Kerosene has the lowest viscosity among the three, followed by water, and mercury has the highest viscosity.Since kerosene has the lowest viscosity, it encounters the least resistance to flow, meaning it will flow out the fastest and empty first.215
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