SSC CHSL - Hydraulics & Fluid Machineries 1000+ MCQ [Solved] PDF Download

1. A hydraulic intensifier normally consists of
A. Two cylinders, two rams and a storage device
B. A cylinder and a ram
C. Two coaxial rams and two cylinders
D. A cylinder, a piston, storage tank and control valve
Answer : C

2. The power produced by the reaction turbine is ________ to the head of water.
A. Directly proportional
B. Inversely proportional
C. 4th power
D. None of these
Answer : A

3. Which of the following turbine is preferred for 0 to 25 m head of water?
A. Pelton wheel
B. Kaplan turbine
C. Francis turbine
D. None of these
Answer : B

4. The discharge through a reaction turbine ________ with the increase in unit speed.
A. Decreases
B. Increases
C. Remain same
D. None of these
Answer : A

5. Multistage centrifugal pumps are used to
A. Give high discharge
B. Produce high heads
C. Pump viscous fluids
D. All of these
Answer : B

6. Which of the following pump is suitable for small discharge and high heads?
A. Centrifugal pump
B. Axial flow pump
C. Mixed flow pump
D. Reciprocating pump
Answer : D

7. The depth of the bucket for a Pelton wheel is generally ________ the diameter of jet.
A. Equal to
B. 1.2 times
C. 1.8 times
D. Double
Answer : B

8. The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which
A. Delivers unit discharge under unit head
B. Delivers unit discharge under unit speed
C. Develops unit power under unit head
D. Develops unit power under unit speed
Answer : C

9. Overall efficiency of a centrifugal pump is the ratio of
A. Energy available at the impeller to the energy supplied to the pump by the prime mover
B. Actual workdone by the pump to the energy supplied to the pump by the prime mover
C. Energy supplied to the pump to the energy available at the impeller
D. Manometric head to the energy supplied by the impeller per kN of water
Answer : B

10. The specific speed of a hydraulic turbine depends upon
A. Speed and power developed
B. Discharge and power developed
C. Speed and head of water
D. Speed, power developed and head of water
Answer : D

11. The runaway speed of a hydraulic turbine is the speed
A. At full load
B. At which there will be no damage to the runner
C. Corresponding to maximum overload permissible
D. At which the turbine will run freely without load
Answer : D

12. The static head of a centrifugal pump is equal to the ________ of suction head and delivery head.
A. Product
B. Difference
C. Sum
D. None of these
Answer : C

13. A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is ________ of the jet velocity
A. One-half
B. One-third
C. Two-third
D. Three-fourth
Answer : B

14. Slip of a reciprocating pump is negative, when
A. Suction pipe is short and pump is running at low speeds
B. Delivery pipe is long and pump is running at high speeds
C. Suction pipe is short and delivery pipe is long and the pump is running at low speeds
D. Suction pipe is long and delivery pipe is short and the pump is running at high speeds
Answer : D

15. Which of the following pump is successfully used for lifting water to the turbines?
A. Centrifugal pump
B. Reciprocating pump
C. Jet pump
D. Air lift pump
Answer : C

16. The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by
A. [2(V_r - v) v]/ V_r²
B. 2(V_r + v) v]/ V_r²
C. [(V_r - v) v]/ V_r
D. [(V_r + v) v]/ V_r
Answer : A

17. Manometric head, in case of a centrifugal pump, is equal to
A. Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe
B. Workdone per kN of water Losses within the impeller
C. Energy per kN at outlet of impeller Energy per kN at inlet of impeller
D. All of the above
Answer : D

18. The jet ratio is defined as the ratio of the
A. Diameter of jet to the diameter of Pelton wheel
B. Velocity of jet to the velocity of Pelton wheel
C. Diameter of Pelton wheel to the diameter of jet
D. Velocity of Pelton wheel to the velocity of jet
Answer : C

19. In a centrifugal pump casing, the flow of water leaving the
A. Radial
B. Axial
C. Centrifugal
D. Vortex
Answer : D

20. When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be
A. Horizontal
B. Nearly horizontal
C. Steep
D. First rise and then fall
Answer : C

21. The angle of taper on draft tube is
A. Greater than 15°
B. Greater than 8°
C. Greater than 5°
D. Less than 8°
Answer : D

22. The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
A. 40 %
B. 50 %
C. 60 %
D. 80 %
Answer : B

23. A double overhung Pelton wheel has
A. Two jets
B. Two runners
C. Four jets
D. Four runners
Answer : B

24. Medium specific speed of a pump implies it is
A. Centrifugal pump
B. Mixed flow pump
C. Axial flow pump
D. Any one of the above
Answer : B

25. Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of
A. 39.2 %
B. 49.2 %
C. 68.8 %
D. 84.8 %
Answer : D

26. Which of the following turbine is preferred for a specific speed of 60 to 300 r.p.m.?
A. Pelton wheel
B. Francis turbine
C. Kaplan turbine
D. None of these
Answer : B

27. The hydraulic efficiency of an impulse turbine is the
A. Ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
B. Ratio of the actual work available at the turbine to the energy imparted to the wheel
C. Ratio of the work done on the wheel to the energy of the jet
D. None of the above
Answer : C

28. The hydraulic efficiency of a reaction turbine, is the ratio of
A. Power produced by the turbine to the energy actually supplied by the turbine
B. Actual work available at the turbine to energy imparted to the wheel
C. Workdone on the wheel to the energy (or head of water) actually supplied to the turbine
D. None of the above
Answer : C

29. Pressure intensifier increases the pressure in proportion to
A. Ratio of diameters
B. Square of ratio of diameters
C. Inverse ratio of diameters
D. Square of inverse ratio of diameters
Answer : B

30. Which of the following is not a reaction turbine?
A. Fourneyron turbine
B. Journal turbine
C. Thomson's turbine
D. Pelton wheel
Answer : D

31. The cavitation in reaction turbines is avoided, to a great extent by
A. Installing the turbine below the tail race level
B. Using stainless steel runner of the turbine
C. Providing highly polished blades to the runner
D. All of the above
Answer : D

32. According to fan laws, at constant speed and capacity, the pressure and power vary
A. Directly as the air or gas density
B. Inversely as square root of density
C. Inversely as density
D. As square of density
Answer : A

33. One horsepower is equal to
A. 102 watts
B. 75 watts
C. 550 watts
D. 735 watts
Answer : D

34. The specific speed of a centrifugal pump, delivering 750 litres of water per second against a head of 15 metres at 725 r.p.m., is
A. 24.8 r.p.m.
B. 48.2 r.p.m
C. 82.4 r.p.m.
D. 248 r.p.m
Answer : C

35. A ship with jet propulsion draws water through inlet orifices at right angles to the direction of its motion. The propelling force of the jet is (where a = Area of the jet, Vr = Relative velocity of the jet and ship = V + v, v = Velocity of the ship, and V = Velocity of the jet issuing from the ship)
A. waVr /g × (Vr + v)
B. waVr /g × (Vr - v)
C. waVr /g × (Vr + v)²
D. waVr /g × (Vr - v)²
Answer : B

36. In centrifugal pumps, maximum efficiency is obtained when the blades are
A. Straight
B. Bent forward
C. Bent backward
D. Radial
Answer : C

37. Medium specific speed of turbine implies it is
A. Propeller turbine
B. Francis turbine
C. Impulse turbine
D. Any one of the above
Answer : B

38. The unit discharge through the turbine is
A. Q/?H
B. Q/H
C. Q/H^3/2
D. Q/H²
Answer : A

39. According to fan laws, at constant pressure, the speed capacity and power vary
A. Directly as the air or gas density
B. Inversely as square root of density
C. Inversely as density
D. As square of density
Answer : B

40. If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge
A. Same quantity of liquid
B. 0.75 Q
C. Q/0.75
D. 1.5 Q
Answer : A

41. The force exerted by a jet of water impinging normally on a plate which due to the impact of jet, moves in the direction of jet with a velocity v is
A. [wa (V - v)]/2g
B. [wa (V - v)]/g
C. [wa (V - v)²]/2g
D. [wa (V - v²)]/g
Answer : D

42. Delivery head of a centrifugal pump is
A. Directly proportional to N
B. Inversely proportional to N
C. Directly proportional to N²
D. Inversely proportional to N²
Answer : C

43. Which of the following statement is correct?
A. The centrifugal pump is suitable for large discharge and smaller heads.
B. The centrifugal pump requires less floor area and simple foundation as compared to reciprocating pump.
C. The efficiency of centrifugal pump is less as compared to reciprocating pump.
D. All of the above
Answer : D

44. The power developed by a turbine is (where H = Head of water under which the turbine is working)
A. Directly proportional to H^1/2
B. Inversely proportional to H^1/2
C. Directly proportional to H^3/2
D. Inversely proportional to H^3/2
Answer : C

45. High specific speed of turbine implies it is
A. Propeller turbine
B. Francis turbine
C. Impulse turbine
D. None of the above
Answer : A

46. Braking jet in an impulse turbine is used
A. To break the jet of water
B. To bring the runner to rest in a short time
C. To change the direction of runner
D. None of these
Answer : B

47. Motion of a liquid in a volute casing of a centrifugal pump is an example of
A. Rotational flow
B. Radial
C. Forced spiral vortex flow
D. Spiral vortex flow
Answer : D

48. Power required to drive a centrifugal pump is directly proportional to ________ of its impeller.
A. Diameter
B. Square of diameter
C. Cube of diameter
D. Fourth power of diameter
Answer : D

49. A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the
A. Kinetic head
B. Velocity head
C. Manometric head
D. Static head
Answer : C

50. An impulse turbine is used for
A. Low head of water
B. High head of water
C. Medium head of water
D. High discharge
Answer : B