Ace the Engineering Utilities 2 – Mechanical Exam 2025: Gear Up for Success!

The venturi effect refers to the phenomenon that occurs when a fluid flows through a constriction in a pipe or tube, resulting in a notable change in pressure and velocity. As the fluid passes through the narrower section, its velocity increases due to the principle of conservation of mass, which states that mass must be conserved in a closed system. According to Bernoulli's principle, an increase in the fluid's velocity leads to a decrease in its pressure. Thus, the reduction in fluid pressure when flowing through a constricted section of pipe is a direct consequence of this effect.

Understanding this principle is crucial in various engineering applications, such as in the design of Venturi meters, which measure fluid flow by utilizing the change in pressure created by the venturi effect. The other choices do not accurately describe this effect; for instance, while there is an increase in fluid velocity (the first choice), it does not directly capture the essential characteristic of the pressure drop associated with the phenomenon. Similarly, changes in temperature or pressure in wider sections of pipes do not pertain to the venturi effect specifically. Therefore, it is the reduction in fluid pressure that encapsulates the essence of the venturi effect.