I'm doing a question relating to the pressure inside on object submerged in water. Here is the question: A tube, height 1.2m, is submerged vertically in the ocean where the waters density is 10^3 kg/m^3. A diver initially holds the tube vertically directly on top of the water. He then dives to a certain depth where the water reaches a height 40cm, from the bottom of the tube. The tube is open at the bottom and closed at the top. Calculate the depth to which he dived. The relevant equations would be P = ro*g*h where h is the depth to which he dived. But I'm unable to calculate the pressure inside the tube and relate it to the pressure outside.