One means of determining the surface level of liquid in a tank is by discharging a small amount of air through a small tube, the end of which is submerged in the tank containing liquid of specific gravity 0.85, and reading the pressure on the gauge that is tapped into the tube. The level of the liquid surface in the tank can then be calculated. Write an equation to relate air pressure p to depth d in the tank. If the pressure on the gauge is 30 kPa, calculate the depth d of the liquid in the tank. Refer to the adjoining sketch for dimensions. Air Supply 1 m T