McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Civil Engineering , Mechanical Engineering .
Chapters
| 1. |
The force exerted by a jet of water on a moving vertical plate, in the direction of motion of plate is given by |
| A. | ρaV2 |
| B. | ρaV3 |
| C. | ρa (V – u)2 |
| D. | ρa (V – u)3 |
| Answer» C. ρa (V – u)2 | |
| 2. |
When a steady jet impinges on a fixed inclined surface |
| A. | The flow is divided into parts proportional to the angle of inclination of the surface |
| B. | No force is exerted by the jet on the vane |
| C. | The momentum component is unchanged parallel to the surface |
| D. | None of the above. |
| Answer» A. The flow is divided into parts proportional to the angle of inclination of the surface | |
| 3. |
For maximum efficiency of a series of curved vanes, the speed is |
| A. | Equal to the jet speed |
| B. | 3/4 of the jet speed |
| C. | 1/2 of the jet speed |
| D. | 1/3 of the jet speed. |
| Answer» C. 1/2 of the jet speed | |
| 4. |
The efficiency of jet propulsion with inlet orifices at right angles to the direction of motion of ship is given by |
| A. | 2u/ (V + u) |
| B. | 2V/ (V + u) 2 |
| C. | 2Vu/ (V + u) 2 |
| D. | 2u (V-u)/V3 |
| Answer» B. 2V/ (V + u) 2 | |
| 5. |
For an impulse turbine which of the following statements is correct : |
| A. | It makes use of a draft tube |
| B. | It is not exposed to atmosphere |
| C. | It is most suited for low head installations |
| D. | It operates with initial complete conversion of pressure head to velocity head. |
| Answer» D. It operates with initial complete conversion of pressure head to velocity head. | |
| 6. |
Which of the following statements is correct in case of a Pelton wheel : |
| A. | It can operate at optimum efficiency at all high speeds |
| B. | It is kept entirely submerged in water below the tail race. |
| C. | It gives optimum efficiency at runaway speed |
| D. | It operates by converting the available energy fully into kinetic energy before entering the rotor. |
| Answer» D. It operates by converting the available energy fully into kinetic energy before entering the rotor. | |
| 7. |
The effective (or net) head at the turbine is |
| A. | The sum of gross head plus head loss in penstock and the velocity head at the turbine exit. |
| B. | The difference between gross head minus the head loss in penstock |
| C. | The difference between the gross head minus head loss in penstock and the velocity head at the turbine exit |
| D. | The sum of gross head plus the head loss in the penstock. |
| Answer» C. The difference between the gross head minus head loss in penstock and the velocity head at the turbine exit | |
| 8. |
The difference between the power obtained from the turbine shaft and power supplied by water at its entry to the turbine is equal to |
| A. | Sum of hydraulic and mechanical losses |
| B. | Sum of mechanical and volumetric losses |
| C. | Mechanical losses |
| D. | Hydraulic losses. |
| Answer» A. Sum of hydraulic and mechanical losses | |
| 9. |
Which of the following statements is a definition of the hydraulic efficiency of a turbine? |
| A. | The ratio of power available at the turbine shaft to that supplied to it by runner. |
| B. | The ratio of the power supplied by the runner to the power available at the shaft. |
| C. | The ratio of power utilized by runner to that supplied by the water at entry to the turbine. |
| D. | The ratio of power supplied by water at entry to the power utilized by runner. |
| Answer» C. The ratio of power utilized by runner to that supplied by the water at entry to the turbine. | |
| 10. |
The power which appears in the expression for the specific speed is the: |
| A. | Shaft power |
| B. | Water power |
| C. | Power into the turbine |
| D. | None of the above. |
| Answer» A. Shaft power | |
| 11. |
Which of the following statements is correct: Runaway speed of a hydraulic turbine is the speed |
| A. | At which there would be no damage to the turbine runner |
| B. | At which the turbine runner can be allowed to run freely without load and with wicket gates wide open |
| C. | Corresponding to maximum overload permissible |
| D. | At full load. |
| Answer» B. At which the turbine runner can be allowed to run freely without load and with wicket gates wide open | |
| 12. |
Which of the following statements is correct for a reaction turbine? |
| A. | The outlet must be above the tail race. |
| B. | Water may be allowed to enter a part or whole of wheel circumference. |
| C. | Flow can be regulated without loss. |
| D. | There is only partial conversion of available head to velocity head before entry to rotor. |
| Answer» D. There is only partial conversion of available head to velocity head before entry to rotor. | |
| 13. |
In a reaction turbine the function of a draft tube is to |
| A. | Provide safety to turbine |
| B. | Prevent air from entering |
| C. | Reconvert the kinetic energy to flow energy |
| D. | Increase the rate of flow |
| Answer» C. Reconvert the kinetic energy to flow energy | |
| 14. |
Which of the following statements with respect to a reaction water turbine is incorrect: |
| A. | The spiral casing serves to uniformly distribute water into guide blades |
| B. | The water leaves the turbine at atmospheric pressure |
| C. | The draft tube allows setting of the turbine above the tail race with minimum reduction of available energy |
| D. | The guide vanes direct the flow at proper angle. |
| Answer» B. The water leaves the turbine at atmospheric pressure | |
| 15. |
Which of the following turbines is suitable for specific speed ranging from 300 to 1000 and heads below 30 m: |
| A. | Francis |
| B. | Kaplan |
| C. | Propeller |
| D. | Pelton. |
| Answer» B. Kaplan | |
| 16. |
Specific speed of a turbo-machine |
| A. | Relates the shape rather than the size of the machine |
| B. | Remains unchanged under different condi tions of operation |
| C. | Has the dimensions of rotational speed |
| D. | Is the speed of a machine having unit dimensions. |
| Answer» A. Relates the shape rather than the size of the machine | |
| 17. |
In an outward radial flow turbine energy conversion process is |
| A. | Purely by reaction only |
| B. | Purely by impulse only |
| C. | Partly by impulse and partly by reaction |
| D. | None of the above. |
| Answer» D. None of the above. | |
| 18. |
Which of the following turbines is least efficient under part load conditions: |
| A. | Propeller |
| B. | Kaplan |
| C. | Francis |
| D. | Pelton. |
| Answer» A. Propeller | |
| 19. |
A surge tank is used to |
| A. | Prevent occurrence of hydraulic jump |
| B. | Smoothen the flow |
| C. | Relieve the pipeline of excessive pressure transients |
| D. | Avoid reversal of flow. |
| Answer» C. Relieve the pipeline of excessive pressure transients | |
| 20. |
Which of the following turbines is most efficient at partload operation? |
| A. | Kaplan |
| B. | Propeller |
| C. | Francis |
| D. | Pelton wheel. |
| Answer» A. Kaplan | |
| 21. |
With respect to a Kaplan turbine which of the following statements is incorrect? |
| A. | It employs large guide vane angles than is the case for a Francis turbine. |
| B. | It is designed for flow velocity of mixed flow type. |
| C. | It has blades of small camber to prevent separation. |
| D. | It can adjust both guide vane and blade angles according to rate of discharge. |
| Answer» B. It is designed for flow velocity of mixed flow type. | |
| 22. |
Specific speed of an impulse turbine (Pelton wheel) ranges from |
| A. | 12 to 70 |
| B. | 80 to 400 |
| C. | 300 to 1000 |
| D. | 1000 to 1200. |
| Answer» A. 12 to 70 | |
| 23. |
Cavitation damage in turbine runner occurs near the |
| A. | Inlet on the convex side of blades |
| B. | Outlet on the convex side of blades |
| C. | Inlet on the concave side of blades |
| D. | Outlet on the concave side of blades. |
| Answer» B. Outlet on the convex side of blades | |
| 24. |
Which of the following serious problems arise from cavitation? |
| A. | Noise and vibration. |
| B. | Damage to blade surface. |
| C. | Fall in efficiency. |
| D. | All of the above. |
| Answer» D. All of the above. | |
| 25. |
A Kaplan turbine is |
| A. | An inward flow impulse turbine |
| B. | Low head axial flow turbine |
| C. | High head axial flow turbine |
| D. | High head mixed flow turbine. |
| Answer» B. Low head axial flow turbine | |
| 26. |
An impulse turbine requires |
| A. | High head and small quantity of flow |
| B. | Low head and small quantity of flow |
| C. | Low head and high rate of flow |
| D. | None of the above |
| Answer» A. High head and small quantity of flow | |
| 27. |
......of a turbine is defined as the ratio of power available at the turbine shaft to the power supplied by the water jet. |
| A. | Mechanical efficiency |
| B. | Hydraulic efficiency |
| C. | Overall efficiency |
| D. | Volumetric efficiency. |
| Answer» C. Overall efficiency | |
| 28. |
The ratio of power developed by the runner to the power supplied by the jet at entrance to the turbine is known as |
| A. | Hydraulic efficiency |
| B. | Mechanical efficiency |
| C. | Volumetric efficiency |
| D. | Overall efficiency. |
| Answer» A. Hydraulic efficiency | |
| 29. |
The water which acts on the runner blades of a reaction turbine is under a pressure |
| A. | Equal to atmospheric |
| B. | Below atmospheric |
| C. | Above atmospheric |
| D. | None of the above. |
| Answer» C. Above atmospheric | |
| 30. |
The runner passages of a reaction turbine are |
| A. | Partially filled with water |
| B. | Always completely filled with water |
| C. | Never filled with water |
| D. | None of the above. |
| Answer» B. Always completely filled with water | |
| 31. |
The value of speed ratio (Ku) in case of a Francis turbine ranges from |
| A. | 0.2 to 0.3 |
| B. | 0.4 to 0.5 |
| C. | 0.6 to 0.9 |
| D. | None of the above. |
| Answer» C. 0.6 to 0.9 | |
| 32. |
The value of flow ratio (Kf) in case of a Francis turbine varies from: |
| A. | 0.1 to 0.14 |
| B. | 0.15 to 0.30 |
| C. | 0.35 to 0.5 |
| D. | 0.6 to 0.9. |
| Answer» B. 0.15 to 0.30 | |
| 33. |
A Kaplan turbine claims which of the following advantages over a Francis turbine? |
| A. | More compact in construction and smaller in size. |
| B. | Partload efficiency is considerably high. |
| C. | Low frictional losses. |
| D. | All of the above. |
| Answer» D. All of the above. | |
| 34. |
Which of the following draft tubes is suited particularly for helical flow? |
| A. | Conical type draft tube. |
| B. | Elbow type draft tube. |
| C. | Moody’s spreading draft tube. |
| D. | None of the above. |
| Answer» C. Moody’s spreading draft tube. | |
| 35. |
Which of the following surge tank is also called a throttled surge tank? |
| A. | Inclined surge tank. |
| B. | Expansion chamber surge tank. |
| C. | Restricted orifice surge tank. |
| D. | None of the above |
| Answer» C. Restricted orifice surge tank. | |
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