12. The hydraulic radius of a non-circular conduit is defined as A. The radius of an equivalent circular conduit. B. The ratio of the cross-sectional area of flow to the wetted perimeter. C. The ratio of the Reynolds Number to the roughness coefficient. D. The hydraulic diameter of an equivalent circular conduit. E. The ratio of the conduit area to its perimeter. 13. If the speed of an incompressible fluid is 4 m/s in a 240-mm- diameter pipe that enters a 160-mm-diameter pipe, what will the speed in the 160-mm-diameter pipe most nearly be? A. 16.0 m/s B. 10.7 m/s C. 9.00 m/s D. 4.00 m/s E. 2.00 m/s 14. Water flows through a multi-sectional pipe placed horizontally on the ground. The velocity is 3.0 m/s at the entrance and 2.1 m/s at the exit. What is the pressure difference between these two points? Neglect friction. A. 0.2 kPa B. 110 kPa C. 28 kPa D. 2.3 kPa 15. Select the false statement for the Bernoulli equation. A. It is valid for unsteady flow. B. It is valid along a streamline. C. It is valid in an inertial coordinate system. D. It is valid for inviscid flow.