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°C. The bell is lowered into the ocean until its lower end is 100 m deep. The temperature at that depth is 10°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?