Question

A vacuum gauge indicates that the pressure of air in a closed chamber is 02 bar ( vacuum) The pressure of the surrounding atmosphere is equivalent to 750 in of mercury The density of mercury is 13.95 g/ cn and the acceleration of gravity is 9.8. / Determine the absolute pressure within the chamber in bar.​

Answer 1

Answer:

Pvac = 0.2 bar

Patm = 750 mm Hg

P Hg = 13.59 g/cm^3 * (1kg/10^3g) (10^2cm/1m)^3 = 13590 kg/m^3

g = 9.81 m/s^2

Patm = P Hg*g*L Hg

= 13590 kg/m^3 * (9.81 m/s^2) * (0.75 m)

= 100 * 10^3 * 1N/1kgms^-2 * 1 bar / 10^5 Nm^-2

= 1 bar

Pabs = Patm - Pvac = 1-0.2

= 0.8 bar