A long glass tube is evacuated and sealed shut at both ends
A long glass tube is evacuated and sealed shut at both ends. It is held in a vertical position, and the bottom end is inserted in a dish of mercury at atmospheric pressure. When a hole is punched in the bottom, how high does the mercury rise in the tube? If the same tube is inserted in a dish of water, how high will the water rise? (The density of mercury is 13.5 g/cm^3. The density of water is 1 g/cc. Assume the tube is long enough so that the liquid doesn\'t hit the top.)
Solution
Pressure by the fluid of height h with density = gh , g = 9.8 m/s2
At the bottom of tube is the the fluid surface where pressure is equivalent to 1 atmospheric pressure = 101325 N/m2
h = 101325/g = 10339.29/
For mercury = 13.5 g/cm3 = 13500 kg/m3
hmercury = 76.59 cm
For water = 1 g/cm3 = 1000 kg/m3
hwater = 1033.93 cm
