Certified Hyperbaric Technologist Test Hyperbaric Physics Fundamentals 3 — Questions and Answers
Question 1: Henry's Law describes which physical phenomenon relevant to hyperbaric therapy?
- Gas volume changes with temperature
- Amount of gas dissolved in a liquid is proportional to its partial pressure (Correct answer)
- Light refraction in water
- Heat transfer in gases
Correct answer: Amount of gas dissolved in a liquid is proportional to its partial pressure
Henry's Law states the quantity of gas dissolving in a liquid is proportional to its partial pressure.
Question 2: Increased dissolved oxygen in plasma during HBOT is best explained by which law?
- Boyle's Law
- Charles's Law
- Henry's Law (Correct answer)
- Newton's Law
Correct answer: Henry's Law
Henry's Law explains greater oxygen partial pressure dissolves more oxygen directly into plasma.
Question 3: Dalton's Law of partial pressures states that the total pressure of a gas mixture equals what?
- The pressure of the heaviest gas
- The sum of the partial pressures of each gas (Correct answer)
- The average of all gas pressures
- The product of the gas concentrations
Correct answer: The sum of the partial pressures of each gas
Dalton's Law states total pressure equals the sum of each component gas's partial pressure.
Question 4: In air (21% oxygen) at 3 ATA, what is the approximate partial pressure of oxygen?
- 0.21 ATA
- 0.63 ATA (Correct answer)
- 1.0 ATA
- 3.0 ATA
Correct answer: 0.63 ATA
Partial pressure equals fraction times total pressure: 0.21 multiplied by 3 ATA equals 0.63 ATA.
Question 5: Why does the risk of oxygen toxicity increase as treatment pressure rises?
- Oxygen molecules become heavier
- The partial pressure of oxygen increases per Dalton's Law (Correct answer)
- Temperature decreases
- Nitrogen is removed
Correct answer: The partial pressure of oxygen increases per Dalton's Law
Higher total pressure raises oxygen's partial pressure, increasing toxicity risk.
Question 6: When a diver breathes compressed air at depth, which gas primarily dissolves into body tissues and causes decompression sickness risk?
- Oxygen
- Carbon dioxide
- Nitrogen (Correct answer)
- Helium
Correct answer: Nitrogen
Inert nitrogen dissolves into tissues under pressure and forms bubbles if ascent is too rapid.
Question 7: What is the partial pressure of oxygen when breathing 100% oxygen at 2.4 ATA?
- 1.0 ATA
- 2.4 ATA (Correct answer)
- 0.21 ATA
- 4.8 ATA
Correct answer: 2.4 ATA
With 100% oxygen the partial pressure equals the total pressure, so it is 2.4 ATA.
Certified Hyperbaric Technologist Test Hyperbaric Physics Fundamentals 3
Henry's Law describes which physical phenomenon relevant to hyperbaric therapy?