Question 561General Subjects - Assistant Engineer

The correct answer is C) Venturi tube. The Venturi tube works on the constriction type, differential head principle. As the flow passes through the constriction in the Venturi tube, it creates a pressure drop that can be measured to determine the flow rate. This is based on the Bernoulli's principle, where the pressure decreases as the flow velocity increases through the constriction. The other options, such as turbine, vortex, and magnetic flow meters, work on different principles and are not considered constriction type, differential head flow meters.