Quiznetik

Hydraulics Machines | Set 2

1. Which of the following pump is sucessfully used for lifting water to the boilers?

Correct : C. Jet pump

2. The flow ratio in case of Francis turbine varies from

Correct : A. 0.15 to 0.3

3. Which type of the pump is defferent from others in the same group?

Correct : D. Plunger pump

4. The ratio of actual work available at the turbine to the energy imparted to the wheel is known as

Correct : B. mechanical

5. The working of which of the following hydraulic units is based on Pascal's law?

Correct : D. Hydraulic press

6. A draft tube is used with impulse turbines.

Correct : B. No

7. The static head of a centrifugal pump is equal to the

Correct : C. sum

8. The overall efficiency of an impulse turbine is the ratio of the actual power produced by the turbine to the energy actually supplied by the turbine.

Correct : A. Yes

9. A jet of water enters and leaves a fixed curved vane tangentially. The force of jet along perpendicular to the vane is zero.

Correct : B. False

10. A Francis turbine is an outward flow reaction turbine.

Correct : B. False

11. The mechanical efficiency of an impulse turbine is

Correct : B. ratio of the actual work available at the turbine to the energy imparted to the wheel

12. In a Francis turbine runner, the number of blades are generally between

Correct : D. 16 to 24

13. The function of guide vanes in a reaction turbine is to

Correct : D. all of the above

14. If the net positive suction head (NPSH) requirement for the pump is not satisfied, then

Correct : B. cavitation will be formed

15. Manometric head is the actual head of water against which a centrifugal pump has to work

Correct : A. Right

16. The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is

Correct : B. 50%

17. A reciprocating pump is also called a

Correct : A. positive

18. Which of the following statement is correct?

Correct : C. In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure

19. If the ratio of all the corresponding linear dimensions are equal, then the model and the prototype are said to have

Correct : A. geometric similarity

20. If the ratios of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have.

Correct : C. dynamic similarity

21. Which of the following pump is sucessfully used for lifting water to the turbines?

Correct : C. Jet pump

22. A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the

Correct : C. manometric head

23. In a Francis turbine, the pressure at inlet is

Correct : B. more than

24. The maximum number of jets, generally, employed in an impulse turbine without jet interference are

Correct : C. six

25. Which of the following hydraulic unit is used for transmitting increased or decreased torque to the driven shaft?

Correct : C. Hydraulic torque converter

26. The head available at the inlet of the turbine is known as net or effective head.

Correct : A. Correct

27. A double overhung Pelton wheel has

Correct : B. two runners

28. The air vessel, in a reciprocating pump, is a cast iron closed chamber having an opening at its base.

Correct : A. Agree

29. The centrifugal pump preferred for a specific speed between 80 to 160 r.p.m. is

Correct : D. high speed with mixed flow at outlet

30. Discharge of a centrifugal pump is

Correct : D. inversely proportional to (diameter)2 of its impeller

31. In an outward flow reaction turbine

Correct : B. the water enters at the centre of the wheel and then flows towards the outer periphery of the wheel

32. Which of the following turbine is preferred for a specific speed of 60 to 300 r.p.m.?

Correct : B. Francis turbine

33. The Thomson's turbine is

Correct : C. an outward flow

34. The power of a centrifugal pump working under constant head and discharge increases with the speed.

Correct : A. True

35. A reciprocating pump is suitable for less discharge and higher heads.

Correct : A. True

36. The breast water wheels are those in which the wheel runs partly by the weight of water and partly by the impulse of water.

Correct : A. True

37. The speed ratio in case of Francis turbine varies from

Correct : C. 0.6 to 0.9

38. Multi-stage centrifugal pumps are used to

Correct : B. produce high heads

39. If the Francis turbine is run below 50 percent head for a long period, it will not only lose its efficiency but also the cavitation danger will become more serious.

Correct : A. Agree

40. The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is

Correct : B. one-half