ANS:B - 10

The percentage of differential pressure lost in a venturi meter with a tapering of 15° is relatively low. It typically ranges from 1% to 10%. Explanation:

• Venturi meters are devices used to measure the flow rate of fluids in a pipeline by utilizing the principle of Bernoulli's equation and the continuity equation.
• The tapering design of the venturi meter allows for the creation of a pressure difference between the inlet and throat sections of the meter, which is proportional to the square of the flow velocity.
• The degree of tapering, represented by the angle of the taper, affects the pressure recovery in the meter.
• A tapering angle of 15° is relatively moderate and allows for good pressure recovery, resulting in a lower percentage of pressure loss compared to more abrupt tapering angles.
• Typically, the percentage of pressure loss in a well-designed venturi meter with a 15° tapering would be around 1% to 10%, depending on various factors such as the Reynolds number, fluid properties, and the accuracy of the meter design and installation.