The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a rectangular notch is given by

A manometer can be used to measure vacuum pressures.

Laminar flow __________ place at very low velocities.

The Francis formula for the discharge over Cippoletti weir is

A vertically immersed surface is shown in the below figure. The distance of its centre of pressure from the water surface is