ANS:A - smaller than

In a standard venturi meter, the exit cone angle is typically smaller than the entrance cone angle. Here’s why:

1. Flow Dynamics: In a venturi meter, fluid enters through a converging section (entrance cone) where the diameter of the pipe gradually decreases. This causes the fluid velocity to increase due to conservation of mass (continuity equation) and decrease in cross-sectional area.
2. Throat: At the narrowest point of the venturi meter, known as the throat, the fluid velocity reaches its maximum while the pressure reaches its minimum.
3. Diverging Section: After passing through the throat, the fluid enters a diverging section (exit cone) where the diameter of the pipe gradually increases again. This section is designed with a slightly smaller cone angle compared to the entrance cone.
4. Purpose: The smaller exit cone angle helps in gradually expanding the flow after the throat, which helps in reducing pressure recovery losses. It also ensures that the flow transitions smoothly back to the original pipe diameter, minimizing turbulence and flow disturbances downstream of the venturi meter.