The correct answer is B. Venturi.
A venturi is a device that is used to measure the flow of a fluid. It consists of a converging section, a throat, and a diverging section. The fluid enters the converging section and is accelerated as it flows through the throat. The pressure in the throat is lower than the pressure in the converging section, and this difference in pressure is used to calculate the flow rate.
An orifice plate is a plate with a hole in it. The fluid flows through the hole and the pressure drop across the hole is used to calculate the flow rate.
A rotameter is a device that uses a rotating element to measure the flow of a fluid. The fluid flows through a tube and the rotating element is suspended in the tube. The speed of rotation of the element is proportional to the flow rate.
A pitot tube is a device that is used to measure the velocity of a fluid. It consists of a tube that is inserted into the fluid and a pressure sensor that is located at the end of the tube. The pressure difference between the pressure at the sensor and the pressure at the ambient air is used to calculate the velocity of the fluid.
The flow of water in a pipe about 3 meters in diameter can be measured by a venturi because it is a device that is specifically designed to measure the flow of fluids. The venturi has a number of advantages over other flow measurement devices, including:
- It is accurate and reliable.
- It is easy to install and maintain.
- It is relatively inexpensive.
- It can be used to measure a wide range of flow rates.
The venturi is a versatile device that can be used to measure the flow of a variety of fluids, including water, oil, and gas. It is a valuable tool for engineers and scientists who need to measure the flow of fluids in a variety of applications.