A hole is made at the bottom of a tank filled with water (density= 10³ kg/m³). If the total pressure at the bottom of the tank is 3 atm (1 atm = 10⁵ N/m²), then the velocity
of efflux is

Total pressure at the bottom = 3 atm
Pressure due to water in the tank = 3 atm - 1 atm = 2 atm = 20 m of water column
Height of water in the tank is h = 20 m
So, velocity of efflux$=\sqrt{2gh}=\sqrt{2\times 10\times 20}=\sqrt{400}=20\mathrm{m}/\mathrm{s}$