Randall D. Knight — A Macroscopic Description of Matter: Problem 50

A diving bell is a 3.0-m-tall cylinder closed at the upper end but open at the lower end. The temperature of the air in the bell is $20^\circ\text{C}$. The bell is lowered into the ocean until its lower end is 100 m deep. The temperature at that depth is $10^\circ\text{C}$. a. How high does the water rise in the bell after enough time has passed for the air inside to reach thermal equilibrium? b. A compressed-air hose from the surface is used to expel all the water from the bell. What minimum air pressure is needed to do this?