At 20 meters depth, the ambient pressure is approximately:

At 20 meters depth, the ambient pressure is approximately:

• A. 2 bar
• B. 3 bar
• C. 4 bar
• D. 5 bar

Answer: (B)

At depth, ambient pressure increases roughly by 1 bar for every 10 meters of seawater, with the surface pressure starting at about 1 bar from the atmosphere. At 20 meters, you have 1 bar of atmospheric pressure plus about 2 bars from the water column, totaling roughly 3 bars of ambient pressure. This matters because gas volume inside lungs and equipment changes with pressure (Boyle’s law), influencing buoyancy and dive planning. The other options correspond to different depths: about 10 meters would give around 2 bars, about 30 meters around 4 bars, and about 40 meters around 5 bars.

At depth, ambient pressure increases roughly by 1 bar for every 10 meters of seawater, with the surface pressure starting at about 1 bar from the atmosphere. At 20 meters, you have 1 bar of atmospheric pressure plus about 2 bars from the water column, totaling roughly 3 bars of ambient pressure. This matters because gas volume inside lungs and equipment changes with pressure (Boyle’s law), influencing buoyancy and dive planning. The other options correspond to different depths: about 10 meters would give around 2 bars, about 30 meters around 4 bars, and about 40 meters around 5 bars.