JEE Main 2024 Physics question
The reading of pressure metre attached with a closed pipe is 4.5 × 10⁴ N/m². On opening the valve, water starts flowing and the reading of pressure metre falls to 2.0 × 10⁴ N/m². The velocity of water is found to be √V m/s. The value of V is .
Answer: 50
Solution
The fall in pressure is ΔP = 2.5 × 10⁴ N/m² = ½ρv². With ρ = 10³ kg/m³: v² = 2 × 2.5 × 10⁴/10³ = 50, so v = √50 m/s and V = 50.