Manometer equilibrium principle

Steps:

• Identify the U-tube as a manometer measuring gas pressure relative to atmospheric pressure.
• Note the height difference Δh between water columns (open side higher by 0.2 m, based on diagram).
• Calculate pressure difference: ρgΔh = (1000 kg/m³)(9.8 m/s²)(0.2 m) ≈ 2000 Pa = 2 kPa.
• Add to atmospheric pressure: P_gas = 101 kPa + 2 kPa = 103 kPa.

Why D is correct:

• Matches the hydrostatic pressure formula P = P_atm + ρgΔh for gas side lower than open side.

Why the others are wrong:

• A: Subtracts difference, implying reversed height (gas side higher).
• B: Ignores height difference entirely.
• C: Uses half the actual Δh or g=10 m/s² approximation error.

Final answer: D