The surface tension of a liquid

A large tank lying on a floor is filled with a liquid of density p. A small hole is made at a depth h below the surface of water in the tank. When the hole is unplugged, the horizontal range of the emerging liquid is R. The horizontal range is doubled if the pressure on the surface of water in the tank is increased by

When capillary tube of radius r is immersed in a liquid of density rho , the liquid rises to a height h in it. If m is the mass of the liquid in the capillary tube, the potential energy of this mass of the liquid in the tube is