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				This section includes 2158 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. | In which of the following methods, the observer concentrates on a point in the fluid system? | 
| A. | Langrangian method | 
| B. | Eulerian method | 
| C. | Any of the above | 
| D. | None of the above. | 
| Answer» E. | |
| 2. | In case of a closed cylindrical vessel sealed at the top and the bottom the volume of air before rotation is ...... the volume of air after: | 
| A. | More than | 
| B. | Less than | 
| C. | Equal to | 
| D. | None of the above | 
| Answer» D. None of the above | |
| 3. | Regarding cavitation which of the following statements in incorrect? | 
| A. | Cavitation affects the performance of a turbine to a lesser degree than that of a pump. | 
| B. | Thoma’s cavitation parameter has different expressions for turbines and pumps. | 
| C. | With the increase in pump speed, there is increase in its minimum net positive suction head requirement. | 
| D. | The leading edge of blades in pumps and the trailing edge of blades in water turbines are more susceptible to cavitation damage | 
| Answer» C. With the increase in pump speed, there is increase in its minimum net positive suction head requirement. | |
| 4. | High velocity flow in a conduit of large size is known as | 
| A. | Laminar flow | 
| B. | Turbulent flow | 
| C. | Either of the above | 
| D. | None of the above. | 
| Answer» C. Either of the above | |
| 5. | The tendency for an immersed body to be lifted up in the fluid, due to an upward force opposite to theaction of gravity is known as | 
| A. | Buoyancy | 
| B. | Centre of buoyancy | 
| C. | Buoyant force | 
| D. | None of the above. | 
| Answer» B. Centre of buoyancy | |
| 6. | ........ is defined as a scalar function of space and time such that its negative derivative with respect to any direction gives the fluid velocity in that direction. | 
| A. | Velocity potential function | 
| B. | Stream function | 
| C. | Circulation | 
| D. | Vorticity. | 
| Answer» B. Stream function | |
| 7. | The pressure gradient in the direction of flow is equal to the shear gradient in the direction | 
| A. | Parallel to the direction of flow | 
| B. | Normal to the direction of flow | 
| C. | Either of the above | 
| D. | None of the above. | 
| Answer» C. Either of the above | |
| 8. | 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» B. Remains unchanged under different condi tions of operation | |
| 9. | The total energy represented by the Bernoulli’s equation (p/ρg +V2/2g +z) has the units: | 
| A. | Nm/s | 
| B. | Ns/m | 
| C. | Nm/m | 
| D. | Nm/N. | 
| Answer» E. | |
| 10. | Compressibility is the reciprocal of | 
| A. | Bulk modulus of elasticity | 
| B. | Shear modulus of elasticity | 
| C. | Young’s modulus of elasticity | 
| D. | Any of the above. | 
| Answer» B. Shear modulus of elasticity | |
| 11. | Darcy-Weisbach equation is used to find loss of head due to : | 
| A. | Sudden enlargement | 
| B. | Sudden contraction | 
| C. | Friction | 
| D. | None of the above. | 
| Answer» D. None of the above. | |
| 12. | Flow in a pipe where average flow parameters are considered for analysis is an example of | 
| A. | Incompressible flow | 
| B. | One-dimensional flow | 
| C. | Two-dimensional flow | 
| D. | Three-dimensional flow. | 
| Answer» C. Two-dimensional flow | |
| 13. | The term........ means the study of pressure exerted by a fluid at rest. | 
| A. | Hydrostatics | 
| B. | Fluid mechanics | 
| C. | Continuum | 
| D. | Kinetics | 
| Answer» B. Fluid mechanics | |
| 14. | 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» D. None of the above. | |
| 15. | 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» D. The sum of gross head plus the head loss in the penstock. | |
| 16. | If velocity potential (φ) satisfies the Laplace equation, it represents the possible..... flow. | 
| A. | Unsteady, compressible, rotational | 
| B. | Steady, compressible, irrotational | 
| C. | Unsteady, incompressible, rotational | 
| D. | Steady, incompressible, irrotational. | 
| Answer» E. | |
| 17. | The delivery valve, while starting centrifugal pump, is kept | 
| A. | Fully closed | 
| B. | Fully open | 
| C. | Half open | 
| D. | In any position. | 
| Answer» B. Fully open | |
| 18. | Which of the following statements is correct with reference to an impeller with backward curved vanes? | 
| A. | It has a falling head - discharge characteristic. | 
| B. | It has rising head - discharge characteristic | 
| C. | It is easier to fabricate. | 
| D. | It cannot run at speeds other than the design speed. | 
| Answer» B. It has rising head - discharge characteristic | |
| 19. | A centrifugal pump should be so installed above the water level in the sump such that | 
| A. | The negative pressures are not allowed to develop in the impeller | 
| B. | The negative pressures do not reach as low a value as the vapour pressure | 
| C. | Its height is more than 10·28 m at ordinary temperature of liquid | 
| D. | None of the above. | 
| Answer» C. Its height is more than 10·28 m at ordinary temperature of liquid | |
| 20. | Which of the following types of impeller is used for centrifugal pumps dealing with muds? | 
| A. | One-side shrouded | 
| B. | Two -sides shrouded | 
| C. | Double section | 
| D. | Open. | 
| Answer» E. | |
| 21. | In a pipe flow the minor losses are those | 
| A. | Which depend on the length of the pipeline | 
| B. | Caused by friction and are thus also called friction losses. | 
| C. | Which have a small magnitude | 
| D. | Which are caused on account of total disturbance produced by such fittings as valves, bends, etc. | 
| Answer» E. | |
| 22. | For turbulent flow in smooth pipes, the entrance length is taken as | 
| A. | 20 | 
| B. | 50 | 
| C. | 80 | 
| D. | 115. | 
| Answer» C. 80 | |
| 23. | The branch of Engineering-science, which deals with water at rest or in motion is called | 
| A. | hydraulics | 
| B. | Fluid mechanics | 
| C. | Applied mechanics | 
| D. | Kinematics. | 
| Answer» B. Fluid mechanics | |
| 24. | When a Pitot-tube is put to use it must be ensured that its alignment is such that: | 
| A. | The horizontal leg should be inclined at 45° in plan | 
| B. | Its horizontal leg is at right angles to the flow direction | 
| C. | Its opening faces upstream and the horizontal leg is perfectly aligned with the direction of flow | 
| D. | None of the above. | 
| Answer» D. None of the above. | |
| 25. | Which of the following is an advantage of dimensional analysis? | 
| A. | It expresses the functional relationship between the variables in dimensionless terms | 
| B. | In hydraulic model studies it reduces the number of variables involved in a physical phenomenon, generally by three | 
| C. | By the use of dimensional analysis design curves can be developed from experimental data or direct solution of the problem | 
| D. | All of the above. | 
| Answer» E. | |
| 26. | The maximum velocity in a circular pipe when flow is laminar occurs at | 
| A. | The top of the pipe | 
| B. | The bottom of the pipe | 
| C. | The centre of the pipe | 
| D. | Not necessarily at the centre. | 
| Answer» D. Not necessarily at the centre. | |
| 27. | The change in moment of momentum of fluid due to flow along a curved path results in: | 
| A. | A change in pressure | 
| B. | Torque | 
| C. | A change in the total energy | 
| D. | None of the above. | 
| Answer» C. A change in the total energy | |
| 28. | 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» C. Never filled with water | |
| 29. | 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» E. | |
| 30. | Higher specific speeds (160 to 500) of centrifugal pump indicate that the pump is of | 
| A. | Radial flow type | 
| B. | Axial flow type | 
| C. | Mixed flow type | 
| D. | Any of these types. | 
| Answer» C. Mixed flow type | |
| 31. | Which of the following devices is used to store energy of liquid under pressure and make this energy available to hydraulic machines? | 
| A. | Hydraulic coupling | 
| B. | Hydraulic accumulator | 
| C. | Hydraulic ram | 
| D. | Hydraulic press. | 
| Answer» C. Hydraulic ram | |
| 32. | In a steady flow the velocity | 
| A. | Does not change from place to place | 
| B. | At a given point does not change with time | 
| C. | May change its direction but the magnitude remains unchanged | 
| D. | None of the above. | 
| Answer» C. May change its direction but the magnitude remains unchanged | |
| 33. | The scale effect in models can be | 
| A. | Positive only | 
| B. | Negative only | 
| C. | Both positive and negative | 
| D. | None of the above. | 
| Answer» D. None of the above. | |
| 34. | Which of the following statements pertaining to a given centrifugal pump is correct? | 
| A. | Discharge varies as the square of speed | 
| B. | Power varies as the square of speed | 
| C. | Discharge varies directly as speed | 
| D. | Head varies inversely as speed. | 
| Answer» D. Head varies inversely as speed. | |
| 35. | The ratio of power developed by the runner to the power supplied by the jet at entrance to the turbine isknown as | 
| A. | Hydraulic efficiency | 
| B. | Mechanical efficiency | 
| C. | Volumetric efficiency | 
| D. | Overall efficiency. | 
| Answer» B. Mechanical efficiency | |
| 36. | The co-efficient of discharge of an orificemeter is ......that of a venturimeter. | 
| A. | Equal to | 
| B. | Much smaller than | 
| C. | Much more than | 
| D. | Any of these. | 
| Answer» C. Much more than | |
| 37. | 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» D. None of the above | |
| 38. | Which of the following turbines is least efficient under part load conditions: | 
| A. | Propeller | 
| B. | Kaplan | 
| C. | Francis | 
| D. | Pelton. | 
| Answer» B. Kaplan | |
| 39. | The function of which of the following hydraulic devices is analogous to that of the flywheel of a reciprocating engine and an electric storage battery? | 
| A. | Hydraulic ram | 
| B. | Hydraulic accumulator | 
| C. | Hydraulic intensifier | 
| D. | Hydraulic coupling. | 
| Answer» C. Hydraulic intensifier | |
| 40. | Dimensional analysis is used to | 
| A. | Test the dimensional homogeneity of any equation of fluid motion | 
| B. | Derive rational formulae for a flow phenomenon | 
| C. | Derive equations expressed in terms of non– dimensional parameters | 
| D. | All of the above. | 
| Answer» E. | |
| 41. | 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» D. The ratio of power supplied by water at entry to the power utilized by runner. | |
| 42. | In case of forced vortex, the rise of liquid level at the ends is .... the fall of liquid level at the axis of rotation. | 
| A. | Less than | 
| B. | More than | 
| C. | Equal to | 
| D. | None of the above | 
| Answer» D. None of the above | |
| 43. | The flow is said to be turbulent when Reynolds number is | 
| A. | Less than 1000 | 
| B. | Equal to 2000 | 
| C. | Greater than 4000 | 
| D. | Between 1000 to 4000. | 
| Answer» D. Between 1000 to 4000. | |
| 44. | Any pressure measured above the absolute zero of pressure is termed as | 
| A. | Atmospheric pressure | 
| B. | Gauge pressure | 
| C. | Either of the above | 
| D. | None of the above | 
| Answer» D. None of the above | |
| 45. | The K.E. correction factor a for a circular pipe is equal to | 
| A. | 2 | 
| B. | 3 | 
| C. | 4 | 
| D. | 6. | 
| Answer» B. 3 | |
| 46. | 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» D. None of the above. | |
| 47. | The efficiency of jet propulsion with inlet orifices at right angles to the direction of motion of ship isgiven by | 
| A. | 2u/ (V + u) | 
| B. | 2V/ (V + u) 2 | 
| C. | 2Vu/ (V + u) 2 | 
| D. | 2u (V-u)/V3 | 
| Answer» C. 2Vu/ (V + u) 2 | |
| 48. | Under which of the following conditions the closure of valve is considered rapid? (where L = length of pipe, C = velocity of pressure wave produced due to water hammer.) | 
| A. | The duration of valve closure is greater than 2L/C | 
| B. | The duration of valve closure is less than L/C | 
| C. | The duration of valve closure is less than 2L/C | 
| D. | None of the above. | 
| Answer» D. None of the above. | |
| 49. | A flow net is a graphical representation of strea lines and equipotential lines such that these lines | 
| A. | Intersect each other orthogonally forming curvilinear squares | 
| B. | Intersect each other at various different angles forming irregular-shaped nets | 
| C. | Indicate the direction and magnitude of vector | 
| D. | None of the above. | 
| Answer» B. Intersect each other at various different angles forming irregular-shaped nets | |
| 50. | Normal acceleration in fluid-flow situation exists only when | 
| A. | The flow is unsteady | 
| B. | The flow is two-dimensional | 
| C. | The streamlines are straight and parallel | 
| D. | The streamlines are curved. | 
| Answer» C. The streamlines are straight and parallel | |