Three identical vessels A, B and C are filled with water, mercury and kerosene respectively up to an equal height. The bottoms of the 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?

The correct answer is D) Vessel C. Here's a brief explanation: 1. Ideal Torricelli's Law: According to the ideal Torricelli's Law (v = sqrt(2gh)), the speed of efflux from an orifice depends only on the height (h) of the liquid and the acceleration due to gravity (g), not on the density or type of liquid. If this ideal law were strictly applied, all three vessels would empty simultaneously. 2. Real-world Factors: However, in real-world scenarios, fluids have properties like viscosity and surface tension that affect their flow through an orifice (tap). * Viscosity: This is a measure of a fluid's resistance to flow. A less viscous fluid flows more easily and quickly. * Surface Tension: This property affects how the liquid interacts with the tap opening and how easily it detaches. Lower surface tension can facilitate flow. 3. Comparing the Liquids: * Kerosene (Vessel C) has significantly lower viscosity and lower surface tension compared to water and mercury. * Water (Vessel A) has intermediate viscosity and surface tension. * Mercury (Vessel B) has the highest viscosity and very high surface tension. 4. Conclusion: Due to its lower viscosity and lower surface tension, kerosene will experience less resistance to flow through the tap. This allows it to flow out at a faster rate than water or mercury, resulting in Vessel C emptying first. Analysis of Options: * A) Vessel B (Mercury): Mercury's high viscosity and surface tension would make it empty the slowest. * B) All the vessels A, B & C will be emptied simultaneously: This would only be true in an ideal, inviscid fluid scenario, which is not realistic for practical taps and liquids. * C) Vessel A (Water): Water would empty faster than mercury but slower than kerosene. * D) Vessel C (Kerosene): Kerosene's lower viscosity and surface tension allow it to flow out most quickly, making it the first to empty.