MCQOPTIONS
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MCQOPTIONS
This section includes 198 Mcqs, each offering curated multiple-choice questions to sharpen your GATE (Mechanical Engineering) knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Theoretical power required (in watts) to drive a reciprocating pump is (where w = Specific weight of liquid to be pumped in N/m3, Q = Discharge of the pump in m3/s, Hs = Suction head in metres, and Hd = Delivery head in metres) |
| A. | wQHs |
| B. | wQHd |
| C. | wQ(Hs - Hd) |
| D. | wQ(Hs + Hd) |
| Answer» E. | |
| 2. |
The unit power developed by a turbine is (where P = Power developed by the turbine under a head of water (H)) |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» D. [D]. | |
| 3. |
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. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» C. [C]. | |
| 4. |
The force exerted (in newton) by a jetof water impinging normally on a fixed plate is (where w = Specific weight of water in N/m3, a = Cross-sectional area of jet in m2, and V = Velocity of jet in m/s) |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» E. | |
| 5. |
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» D. none of the above | |
| 6. |
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» E. | |
| 7. |
In an impulse turbine, the pressure of water both at entering and leaving the vanes, is atmospheric. |
| A. | Agree |
| B. | Disagree |
| C. | Can't say |
| D. | None of these |
| Answer» B. Disagree | |
| 8. |
The specific speed of a turbine is given by the equation |
| A. | N√P / H^3/2 |
| B. | N√P / H² |
| C. | N√P / H^5/4 |
| D. | N√P / H³ |
| Answer» D. N√P / H³ | |
| 9. |
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» D. develops unit power under unit speed | |
| 10. |
The relation between hydraulic efficiency (ηh), mechanical efficiency (ηm) and overall efficiency (ηo) ) is |
| A. | ηh = ηo x ηm |
| B. | ηm = ηo x ηh |
| C. | ηo = ηh x ηm |
| D. | none of these |
| Answer» D. none of these | |
| 11. |
Which of the following statement is correct as regard to water wheels? |
| A. | They have slow speeds. |
| B. | They are suitable even for low water heads. |
| C. | They give constant efficiency, even if the discharge is not constant |
| D. | all of the above |
| Answer» E. | |
| 12. |
The maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet) |
| A. | (1 + cos φ)/2 |
| B. | (1 - cos φ)/2 |
| C. | (1 + sin φ)/2 |
| D. | (1 - sin φ)/2 |
| Answer» B. (1 - cos φ)/2 | |
| 13. |
A Pelton wheel is |
| A. | tangential flow impulse turbine |
| B. | inward flow impulse turbine |
| C. | outward flow impulse turbine |
| D. | inward flow reaction turbine |
| Answer» B. inward flow impulse turbine | |
| 14. |
Which of the following is not a reaction turbine? |
| A. | Furneyron turbine |
| B. | Jonval turbine |
| C. | Thomson's turbine |
| D. | Pelton wheel |
| Answer» E. | |
| 15. |
A double overhung Pelton wheel has |
| A. | two jets |
| B. | two runners |
| C. | four jets |
| D. | four runners |
| Answer» C. four jets | |
| 16. |
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. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» B. No | |
| 17. |
If V1 and V2 are the velocities of water at inlet and outlet of the draft tube respectively, then the efficiency of a draft tube is |
| A. | (V1 - V2) / V1 |
| B. | (V1² - V2²) / V1² |
| C. | V1 / (V1 - V2) |
| D. | V1² / (V1² - V2²) |
| Answer» C. V1 / (V1 - V2) | |
| 18. |
Which of the following pump is sucessfully used for lifting water to the boilers? |
| A. | Centrifugal pump |
| B. | Reciprocating pump |
| C. | Jet pump |
| D. | Air-lift pump |
| Answer» D. Air-lift pump | |
| 19. |
The flow ratio of Francis turbine is defined as the ratio of the |
| A. | velocity of flow at inlet to the theoretical jet velocity |
| B. | theoretical velocity of jet to the velocity of flow at inlet |
| C. | velocity of runner at inlet to the velocity of flow at inlet |
| D. | none of the above |
| Answer» B. theoretical velocity of jet to the velocity of flow at inlet | |
| 20. |
A jet of water enters and leaves a fixed curved vane tangentially. The force of jet along perpendicular to the vane is zero. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 21. |
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» C. 1.8 times | |
| 22. |
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» C. medium head of water | |
| 23. |
The power of a centrifugal pump working under constant head and discharge increases with the speed. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 24. |
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» D. none of the above | |
| 25. |
In a mixed flow reaction turbine, the flow of water is partly radial and partly axial. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» B. Incorrect | |
| 26. |
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» E. | |
| 27. |
If the ratio of all the corresponding linear dimensions are equal, then the model and the prototype are said to have |
| A. | geometric similarity |
| B. | kinematic similarity |
| C. | dynamic similarity |
| D. | none of these |
| Answer» B. kinematic similarity | |
| 28. |
A Kaplan turbine is an axial flow reaction turbine. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» B. Incorrect | |
| 29. |
The overall efficiency for a Pelton wheel lies between |
| A. | 0.50 to 0.65 |
| B. | 0.65 to 0.75 |
| C. | 0.75 to 0.85 |
| D. | 0.85 to 0.90 |
| Answer» E. | |
| 30. |
By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is |
| A. | 39.2% |
| B. | 48, 8% |
| C. | 84.8% |
| D. | 88.4% |
| Answer» D. 88.4% | |
| 31. |
If the ratio of corresponding velocities at corresponding points are equal, then the model and the prototype are said to have dynamic similarity. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 32. |
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» E. | |
| 33. |
Which of the following hydraulic unit is used for transmitting increased or decreased torque to the driven shaft? |
| A. | Hydraulic ram |
| B. | Hydraulic intensifier |
| C. | Hydraulic torque converter |
| D. | Hydraulic accumulator |
| Answer» D. Hydraulic accumulator | |
| 34. |
A hydraulic accumulator is a device used to store __________ energy which may be supplied to a machine later on. |
| A. | strain |
| B. | pressure |
| C. | kinetic |
| D. | None of these |
| Answer» C. kinetic | |
| 35. |
The function of guide vanes in a reaction turbine is to |
| A. | allow the water to enter the runner without shock |
| B. | allow the water to flow over them, without forming eddies |
| C. | allow the required quantity of water to enter the turbine |
| D. | all of the above |
| Answer» E. | |
| 36. |
Which of the following pump is successfully used for lifting water from deep wells? |
| A. | Centrifugal pump |
| B. | Reciprocating pump |
| C. | Jet pump |
| D. | Air lift pump |
| Answer» E. | |
| 37. |
Which of the following is not an impulse turbine? |
| A. | Girad turbine |
| B. | Turgo turbine |
| C. | Pelton wheel |
| D. | Kaplan turbine |
| Answer» E. | |
| 38. |
A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used ? |
| A. | Pelton wheel with one nozzle |
| B. | Pelton wheel with two or more nozzles |
| C. | Kaplan turbine |
| D. | Francis turbine |
| Answer» B. Pelton wheel with two or more nozzles | |
| 39. |
A reciprocating pump is also called a __________ displacement pump. |
| A. | positive |
| B. | negative |
| C. | Can't say |
| D. | None of these |
| Answer» B. negative | |
| 40. |
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» C. to change the direction of runner | |
| 41. |
Head developed by a centrifugal pump is |
| A. | proportional to diameter of impeller |
| B. | proportional to speed of impeller |
| C. | proportional to diameter and speed of impeller |
| D. | none of the above |
| Answer» D. none of the above | |
| 42. |
In a centrifugal pump, the water enters the impeller __________ and leaves the vanes axially. |
| A. | axially |
| B. | radially |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 43. |
Power required to drive a centrifugal pump is __________ proportional to N3. |
| A. | directly |
| B. | inversely |
| C. | Can't say |
| D. | None of these |
| Answer» B. inversely | |
| 44. |
In a Francis turbine, the pressure at inlet is __________ that at outlet. |
| A. | less than |
| B. | more than |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 45. |
The impeller of a centrifugal pump may have |
| A. | volute casing |
| B. | volute casing with guide blades |
| C. | vortex casing |
| D. | any one of these |
| Answer» E. | |
| 46. |
A hydraulic press is a device used |
| A. | to store pressure energy which may be supplied to a machine later on |
| B. | to increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure |
| C. | to lift larger load by the application of a comparatively much smaller force |
| D. | all of the above |
| Answer» D. all of the above | |
| 47. |
The cavitation in a hydraulic machine |
| A. | causes noise and vibration of various parts |
| B. | reduces the discharge of a turbine |
| C. | causes sudden drop in power output and efficiency |
| D. | all of the above |
| Answer» E. | |
| 48. |
If the ratio's of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have. |
| A. | geometric similarity |
| B. | kinematic similarity |
| C. | dynamic similarity |
| D. | none of these |
| Answer» D. none of these | |
| 49. |
The width of the bucket for a Pelton wheel is generally __________ the diameter of jet. |
| A. | double |
| B. | three times |
| C. | four times |
| D. | five times |
| Answer» E. | |
| 50. |
The specific speed of a centrifugal pump may be defined as the speed of an imaginary pump, identical with the given pump, which will discharge one litre of water, while it is being raised through a head of one metre. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |