GATE 2021 IN – Question 29

Sensors and Industrial Instrumentation · Displacement force and pressure measurement · 1 mark · Numerical answer

Given mercury density 13600 kg/m$^3$, gravity 9.81 m/s$^2$, and atmospheric pressure 101 kPa, a mercury U-tube manometer shows liquid-height difference 1 cm. The differential pressure is ______ Pa (nearest integer).

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Correct answer: 1333 to 1360

Explanation

Use the vertical level difference h=0.01 m: Δp=ρgh=13600·9.81·0.01=1334.16 Pa, rounded **1334 Pa**. Atmospheric pressure is common to the differential measurement and is not added.