Question

Which of the following devices is used to measure the rate of flow of liquid through a pipe?
A. Thermometer
B. Barometer
C. Manometer
D. Venturimeter

Answer 1

From the given options, identify the function of the devices. The device used to measure the rate of flow of liquid works on Bernoulli's principle. If you check the name suggested by the device, you will be able to identify the function of the devices.

Complete answer:
To answer this question, let us verify every given option.
Thermometer: We know that the thermometer is the device used to measure the temperature. Therefore, the option A is incorrect.
Barometer: We know that the barometer is a device used to measure the atmospheric pressure or barometric pressure. The layer of air around the earth is affected by the gravity and it presses against the earth. The pressure exerted by this push is measured by the barometer. Therefore, the option B is incorrect.
Manometer: We know that the manometer is a device used to measure the differential pressure. It is used to measure the pressure in the pipes. Therefore, the option C is incorrect.
Venturimeter: The working of the venturimeter is based on Bernoulli’s principle. It measures the rate of flow of fluid in a pipe by reducing the cross-sectional area and creating a pressure difference.

So, the correct answer is option D.

Note: There is a difference in the function of barometer and manometer. The barometer measures only the atmospheric pressure while the manometer measures the differential pressure by subtracting the atmospheric pressure. The nozzle of the venturi meter should be narrow so that it can create the pressure gradient and increase the velocity of the flow.