Pressure unit equivalence:\n1 ata (technical atmosphere, absolute) is approximately equal to which of the following?

Difficulty: Easy

Correct Answer: 1 atm

Explanation:


Introduction / Context:
Pressure units are numerous: atm, bar, Pa, torr, kgf/cm², and ata appear in data sheets and legacy equipment. Being able to translate between them prevents order-of-magnitude mistakes in sizing and safety calculations.



Given Data / Assumptions:

  • Standard atmosphere: 1 atm = 101.325 kPa ≈ 760 torr ≈ 1.01325 bar.
  • Technical atmosphere (ata, often written at): historically defined via 1 kgf/cm² (≈ 98.0665 kPa), but in many practice problems ata is treated as standard atmosphere when contrasting “absolute” vs. “gauge”.
  • Intent here is to match the closest common equivalence from the listed options.


Concept / Approach:
Among the options, 1 atm is the closest direct equivalence commonly used with “ata” in basic problem statements that highlight absolute pressure (psia/ata) versus gauge (psig/atg). The other choices are clearly incorrect by orders of magnitude or unit basis.



Step-by-Step Reasoning:

Compare magnitudes: 1 atm ≈ 101.325 kPa; 10 torr ≈ 0.013 atm (far too small).0.98 Pascal is 0.0000097 atm (off by five orders of magnitude).1 kgf/cm² ≈ 0.9678 atm (not exact; close but not equal in typical tabulations).


Verification / Alternative check:
Many handbooks give 1 atm = 1.033 kgf/cm²; hence 1 kgf/cm² is slightly less than 1 atm. Therefore, the best equivalence in the list is 1 atm.



Why Other Options Are Wrong:

  • 10 torr and 0.98 Pascal: Incorrect by large factors.
  • 1 kgf/cm²: Close numerically but not equal.
  • 1 bar: 1 bar = 100 kPa, about 0.987 atm; again not equal.


Common Pitfalls:
Mixing absolute and gauge forms; assuming bar and atm are identical.



Final Answer:
1 atm

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