Certified Hyperbaric Technologist Practice Test

How can absolute pressure be defined?

1. Only the ambient pressure

2. Gauge pressure combined with external atmospheric pressure

3. The pressure exerted at sea level

4. The force applied per unit area

The correct answer is: Gauge pressure combined with external atmospheric pressure

Absolute pressure is defined as the total pressure measured from absolute zero, which incorporates both the gauge pressure and the atmospheric pressure surrounding a system. When measuring the pressure of a fluid or gas, gauge pressure measures the pressure relative to the atmosphere; therefore, to find absolute pressure, you must add the ambient atmospheric pressure to it. This definition is essential in many scientific and engineering applications, particularly in hyperbaric medicine, where understanding the precise pressure environment is crucial for safety and efficacy. The other options present different concepts that do not fully capture the definition of absolute pressure. While ambient pressure refers to the pressure of the surrounding environment, it does not account for the gauge pressure of a system. The pressure exerted at sea level refers specifically to a standard condition but does not define absolute pressure universally, as it can vary with altitude and weather conditions. Lastly, the measure of force applied per unit area describes pressure in general but does not specify the distinction between absolute, gauge, or atmospheric pressures, which are crucial to understanding pressure measurements in different contexts.