Project ForgeFluid Mechanics
Fluid Statics
GATE 2020
Medium
In the space above the mercury column in a barometer tube, the gauge pressure of the vapour is
- Apositive, but more than one atmosphere
- negative
- Czero
- Dpositive, but less than one atmosphere
Explanation
The Torricelli vacuum space above a barometer's mercury column is at (near) zero absolute pressure. Gauge pressure = absolute − atmospheric ≈ 0 − p_atm, which is negative.
Source: GATE ME 2020 Session 2 (ME-2) (2020)
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