Question

A U-tube manometer is closed at both ends one end is vacuum and other end has a gas, if the difference in level of mercury is h = 10 mm, what is the pressure of gas?

(a) 1.33 Pa

(b) 1.45 Pa

(c) 1.56 Pa

(d) 1.75 Pa

I have been asked this question in an international level competition.

I'm obligated to ask this question of Differential Pressure Measurements topic in division Temperature and Pressure of Basic Chemical Engineering

Answer 1

The correct option is (a) 1.33 Pa

The best I can explain: Since the other end of the manometer has vacuum, this means the pressure of gas is equal to the difference in pressure of mercury in both ends, => Pressure of gas = d*g*h = 13.6*9.8*0.01 = 1.33 Pa.