GATE 2021 CE (CE2) – Question 33
A lake is 60 m deep. Atmospheric pressure is 91 kPa and water unit weight 9790 N/m³. Find absolute pressure at maximum depth in kPa to two decimals.
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Correct answer: 677.50 to 679.50
Explanation
Hydrostatic gauge pressure is $\gamma h=9790(60)=587400$ Pa=587.4 kPa. Absolute pressure adds the atmospheric component: $91+587.4=\mathbf{678.40}$ kPa. Omitting 91 kPa would give gauge rather than absolute pressure.