What is the standard atmospheric pressure at sea level?

The standard atmospheric pressure at sea level is defined as 14.7 pounds per square inch (psi). This value represents the average pressure exerted by the weight of the atmosphere at sea level and is a crucial reference point in many scientific and engineering calculations. Atmospheric pressure varies with altitude, weather, and temperature, but 14.7 psi is the accepted norm under standard conditions, which allows for consistency in measurements across various disciplines.

The other options do not reflect the standard pressure at sea level. For instance, 28.5 psi is significantly higher than normal atmospheric pressure, while 30.0 psi indicates a pressure that would be measured in a high-pressure weather system rather than the average. A value of 15.0 psi is also higher than the standard atmospheric pressure, which must be accurately recognized to understand the principles of fluid dynamics and other applications in water treatment processes.