Atmospheric pressure expressed as an equivalent water column Standard atmospheric pressure at sea level is approximately equal to what head of water?

Introduction / Context:Barometric (atmospheric) pressure is often converted into an equivalent head of a fluid for hydraulic calculations and for calibrating manometers and barometers.

Given Data / Assumptions:

• Standard atmosphere ≈ 101325 Pa.
• Water at about 4–20°C with density near 1000 kg/m^3.

Concept / Approach:Hydrostatic relation: p = rho * g * h ⇒ h = p / (rho * g). Substituting p ≈ 101325 Pa, rho ≈ 1000 kg/m^3, g ≈ 9.81 m/s^2 gives a water head around 10.33 m; many textbooks use 10.3 m.

Step-by-Step Solution:

Verification / Alternative check:In mercury, this corresponds to about 760 mm Hg because mercury is ~13.6 times as dense as water.

Why Other Options Are Wrong:

• 9.81 m: numerically close but underestimates standard atmosphere.
• 5.0 m and 7.5 m: far too low.

Common Pitfalls:Forgetting to use consistent units; using seawater density without noting salinity.

Final Answer:10.30 m