Actual hydro-electric power stations are built so that the height of the water above the turbine is very large. what is the advantage for building hydro-electric power stations in this way. explain your answer.

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.