Figure shows a large closed cylindrical tank containing water. Initially, the air trapped above the water surface has a height $h_0$  and pressure $2P_0$  where $P_0$  is the atmospheric pressure. There is a hole in the wall of the tank at a depth $h_1$ below the top from which water comes out. A long vertical tube is connected as shown. Find the distance of water surface in the long tube from the top of the tank, when the water stops coming out of the hole.