A piezometer is used to measure
Right Answer is:
Very low pressure
SOLUTION
Piezometers are used to monitor pore water pressure and are sometimes referred to as pore pressure cells.
Piezometer tube
The piezometer tube is a vertical glass tube inserted in the wall of a pipe or a vessel containing the liquid whose pressure is to be measured. The tube is kept vertical and its other end is open to the atmosphere. The height of the liquid in the tube above any point in the fluid indicates the pressure of the liquid at that point. In the figure, the pressure at the point above atmospheric pressure is:
PA = whA
where
hA is the height of the liquid column in the piezometer tube.
Since the other end of the tube is open to the atmosphere, the pressure obtained using the piezometer tube is gauge pressure. This type of manometer can only be used for measuring small and moderate pressures because as the pressure to be measured increases, the corresponding length of the piezometer tube required for measurement also increases. When the length of the tube becomes longer, it cannot be handled conveniently.
The piezometer, when used for the measurement of pressure in a pipe in which fluid is flowing, must be kept such that the axis of the tube is normal to the direction of flow. Also, to reduce the surface tension and capillarity effects. the diameter of the tube must be at least 12 mm.