A closed U-tube manometer has a gas on one end with pressure 10 Pa and other end has vacuum, what is the approximate density of the liquid if the height difference of the liquid is 10 cm?

Correct Answer: 10 Kg/m3
Pressure of gas = Pressure due to height difference of liquid = d*g*h, => 10 = d*10*0.1, => d = 10 Kg/m3.