Which of the following corresponds to standard atmospheric pressure in metric units?

• A. 101.3 kPa
• B. 1.013 bar
• C. 1 atm
• D. 14.7 psi

Answer: (C)

Standard atmospheric pressure is defined as the pressure exerted by the weight of the atmosphere at sea level. In metric units, this is commonly represented as 101.3 kilopascals (kPa) or 1.013 bar. The choice identified as the correct answer, "1 atm," is a unit of pressure that is equivalent to these values and is widely used in various scientific and engineering contexts.

The definition of 1 atmosphere (atm) is exactly equal to 101.325 kPa, which is often rounded to 101.3 kPa in many practical applications, reinforcing its significance in representing atmospheric pressure. Additionally, in barometric systems, 1 atm is also acknowledged as roughly 1.013 bar, which is useful in fields involving fluid dynamics and thermodynamics.

Understanding the various units that define atmospheric pressure helps clarify their interrelationships. For instance, while psi (pounds per square inch) is used primarily in American units, 14.7 psi is equal to 1 atm but falls outside the standard metric categorization. Therefore, "1 atm" serves as a direct representation of standard atmospheric pressure and aligns with common scientific standards.