At a pressure of 8.1" hg, what is the atmospheric pressure indicated?

To determine the atmospheric pressure indicated at a pressure reading of 8.1 inches of mercury (hg), it's important to understand the context of pressure measurements. Standard atmospheric pressure at sea level is defined as 14.7 psi (pounds per square inch), which is equivalent to 29.92 inches of mercury.

The reading of 8.1" hg that you have is a measurement of pressure relative to a vacuum, meaning it's a gauge pressure. To convert this into absolute atmospheric pressure, you can use the formula:

1. Convert inches of mercury to psi:

( 1" , hg \approx 0.491 , psi )

2. Thus,

( 8.1" , hg ) can be converted to psi:

( 8.1" , hg \times 0.491 , psi/inch \approx 3.98 , psi )

3. To find the atmospheric pressure, you would take the standard atmospheric pressure (14.7 psi) and add the gauge pressure:

( 14.7 , psi + 3.98 , psi \approx 18.68 , psi )

4. However,