Venturimeter is used to measure
**Core Concept**
The venturimeter is a device used to measure the flow rate of fluids in a pipe. It works on the principle of Bernoulli's equation, which states that the pressure of a fluid decreases as its velocity increases. The venturimeter consists of a constricted section of pipe, which causes the fluid to accelerate and its pressure to decrease.
**Why the Correct Answer is Right**
The venturimeter measures the flow rate of a fluid by measuring the pressure difference between the inlet and outlet of the constricted section. This is based on the principle that the pressure of a fluid is directly proportional to its velocity. As the fluid accelerates through the constricted section, its velocity increases, and its pressure decreases. By measuring the pressure difference, the venturimeter can calculate the flow rate of the fluid. The venturimeter is commonly used in hydraulic and pneumatic systems to measure the flow rate of liquids and gases.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the venturimeter is not used to measure the flow rate of gases in a pipe. While it can be used to measure the flow rate of gases, it is not the most accurate or commonly used device for this purpose.
**Option B:** This option is incorrect because the venturimeter is not used to measure the pressure of a fluid. While it measures the pressure difference between the inlet and outlet of the constricted section, it is not a pressure-measuring device.
**Option C:** This option is incorrect because the venturimeter is not used to measure the volume of a fluid. While it can be used to calculate the flow rate of a fluid, which can then be used to calculate the volume, it is not a direct measure of volume.
**Clinical Pearl / High-Yield Fact**
The venturimeter is a classic example of a device that uses the principle of Bernoulli's equation to measure the flow rate of a fluid. This principle is also used in other devices, such as orifice plates and flow meters, to measure fluid flow.
**Correct Answer: C. Flow rate of fluid**