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Absolute Pressure Formula:
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Absolute pressure is the total pressure measured relative to a perfect vacuum. It is the sum of gauge pressure (pressure relative to atmospheric pressure) and atmospheric pressure.
The calculator uses the absolute pressure formula:
Where:
Explanation: Absolute pressure represents the true thermodynamic pressure and is essential for scientific calculations where vacuum is the reference point.
Details: Absolute pressure is crucial in various engineering applications, including fluid dynamics, thermodynamics, vacuum systems, and weather forecasting. It provides the true pressure value needed for accurate scientific computations.
Tips: Enter gauge pressure and atmospheric pressure in Pascals (Pa). Both values must be non-negative. Standard atmospheric pressure is approximately 101,325 Pa at sea level.
Q1: What is the difference between absolute and gauge pressure?
A: Absolute pressure is measured relative to perfect vacuum, while gauge pressure is measured relative to atmospheric pressure. Gauge pressure can be negative (vacuum), but absolute pressure is always positive.
Q2: What is standard atmospheric pressure?
A: Standard atmospheric pressure at sea level is 101,325 Pascals (Pa), which is equivalent to 1 atmosphere (atm), 760 mmHg, or 14.7 psi.
Q3: When should I use absolute pressure vs gauge pressure?
A: Use absolute pressure for scientific calculations involving gas laws, thermodynamics, and vacuum systems. Use gauge pressure for most industrial applications like tire pressure, hydraulic systems, and pressure vessels.
Q4: Can gauge pressure be negative?
A: Yes, gauge pressure can be negative when the measured pressure is below atmospheric pressure, indicating a vacuum or suction condition.
Q5: How does altitude affect atmospheric pressure?
A: Atmospheric pressure decreases with increasing altitude. At higher elevations, atmospheric pressure is lower than at sea level, which affects the calculation of absolute pressure.