A manometer connected to a closed tap reads 3.5 × 105 N/m2. When the valve is opened, the reading of manometer falls to 3.0 × 105 N/m2, then velocity of flow of water is

Bernoulli's theorem for unit mass of liquid Pρ+12v2= constant As the liquid starts flowing, it pressure energy decreases 12v2=P1−P2ρ⇒12v2=3.5×105−3×105103⇒v2=2×0.5×105103⇒v2=100⇒v=10 m/s