Final answer:
The high pressure gauge on a manifold gauge set is calibrated to read zero at atmospheric pressure. Gauge pressure is the pressure relative to atmospheric pressure. Manometers are used to measure pressure in various applications.
Step-by-step explanation:
The high pressure gauge on a manifold gauge set is calibrated to read zero at atmospheric pressure. This means that when the pressure inside the system is greater than atmospheric pressure, the gauge will display a positive value. The gauge pressure is the pressure relative to atmospheric pressure. To measure gauge pressure using a manometer, you can use a closed-ended manometer or an open-ended manometer.
In a closed-ended manometer, the gas pressure is equal to the height h in mm Hg. On the other hand, in an open-ended manometer, the gas pressure is equal to the difference in the height of mercury in the two arms of the U-tube plus the atmospheric pressure outside. Both types of manometers are commonly used to measure pressure in various applications.