The water manometer above is measuring the pressure of gas supply. if the specific gravity of mercury is 13.6 and the atmospheric pressure is 70cm of mercury what is the total pressure of the gas supply in cm of water
A.
67cm
B.
73cm
C.
949cm
D.
952cm
E.
955cm
Correct answer is E
Atmospheric pressure = 70cmHg (which is the height of mecury)
pressure = pgh = pwghw
Where
Pw = density of water
hw = height of water
ph = pwhw
13.6*70 = 1*hw
hw = 952cm
Pressure of gas in cm of water = 952 + 3 = 955cm