MCQOPTIONS
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MCQOPTIONS
This section includes 88 Mcqs, each offering curated multiple-choice questions to sharpen your Turbo Machines knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
In a velocity compounded steam turbine, as steam moves along moving and guide blades |
| A. | both pressure and velocity gradually decrease |
| B. | Both pressure and velocity gradually increase. |
| C. | pressure gradually increases and velocity is low |
| D. | pressure is low and velocity gradually decreases |
| Answer» E. | |
| 52. |
The effect of blade friction in a steam turbine is to |
| A. | increase the specific output |
| B. | reduce work done |
| C. | reheat the steam |
| D. | reduce exhaust pressure |
| Answer» C. reheat the steam | |
| 53. |
Bleeding in steam turbine refers to |
| A. | purposely withdrawn steam for process application |
| B. | leakage of steam through bearings |
| C. | purposely withdrawn for feed water heating |
| D. | leakage of steam through packings |
| Answer» D. leakage of steam through packings | |
| 54. |
In a modern steam turbine, the steam rte is nearly |
| A. | 1 kg/kWhr |
| B. | 8 kg/kWhr |
| C. | 4 kg/kWhr |
| D. | 2 kg/kWhr |
| Answer» D. 2 kg/kWhr | |
| 55. |
Which of the following steam turbine has identical fixed and moving blades? |
| A. | Curtis turbine |
| B. | Rateau turbine |
| C. | Parson's turbine |
| D. | none of the above |
| Answer» D. none of the above | |
| 56. |
In gas turbines, intercooling results in |
| A. | decrease in net output and increase in thermal efficiency |
| B. | decrease in net output as well as thermal efficiency |
| C. | increase in net output as well as thermal efficiency |
| D. | increase in net output but decrease in thermal efficiency |
| Answer» D. increase in net output but decrease in thermal efficiency | |
| 57. |
Which of the following is the least efficient method of governing steam turbines? |
| A. | Combined throttle and nozzle governing |
| B. | Throttle governing |
| C. | Nozzle control governing |
| D. | Bypass governing |
| Answer» C. Nozzle control governing | |
| 58. |
Generally, steam turbines in power stations operate at |
| A. | 3000 rpm |
| B. | 375 rpm |
| C. | 1000 rpm |
| D. | 1500 rpm |
| Answer» B. 375 rpm | |
| 59. |
Which of the following fluid can be used in binary vapour cycle? |
| A. | Mercury |
| B. | Diphenyl oxide |
| C. | Aluminium bromide |
| D. | any of the above |
| Answer» E. | |
| 60. |
In a gas turbine combined cycle plant, a waste heat boiler is used to |
| A. | heat air from intercooler |
| B. | gases from regenerator |
| C. | recover heat form exhaust gases |
| D. | none of the above |
| Answer» D. none of the above | |
| 61. |
In a two stage gas turbine plant, reheating after first stage |
| A. | increases work ratio |
| B. | decreases work ratio |
| C. | does not affect work ratio |
| D. | none of the above |
| Answer» B. decreases work ratio | |
| 62. |
The following property is the most important for material used for gas turbine blades |
| A. | Fatigue |
| B. | Strength against bending |
| C. | Strength against direct force |
| D. | Group |
| Answer» E. | |
| 63. |
Thermal efficiency of closed cycle gas turbine plant increases by |
| A. | reheating |
| B. | intercooling |
| C. | regenerator |
| D. | All of the above |
| Answer» E. | |
| 64. |
A regenerator can be used on |
| A. | open cycle gas turbines only |
| B. | closed cycle gas turbines only |
| C. | both open as well as closed cycle gas turbines |
| D. | none of the above |
| Answer» D. none of the above | |
| 65. |
Air fuel ratio for a gas turbine is closer to |
| A. | 60 ; 1 |
| B. | 10 ; 1 |
| C. | 15 ; 1 |
| D. | 20 ; 1 |
| Answer» B. 10 ; 1 | |
| 66. |
With increase in pressure ratio, thermal efficiency of a simple gas turbine plant with fixed turbine inlet temperature |
| A. | increases |
| B. | decreases |
| C. | first increases and then decreases |
| D. | none of the above |
| Answer» D. none of the above | |
| 67. |
In a nozzle if back pressure is equal to inlet pressure |
| A. | maximum flow occurs |
| B. | no flow occurs |
| C. | flow is subsonic in diverging section |
| D. | flow is supersonic in converging as well as supersonic sections |
| Answer» C. flow is subsonic in diverging section | |
| 68. |
Which gas turbine has lest weight per bhp developed? |
| A. | Simple open cycle gas turbine |
| B. | Open cycle gas turbine with intercooling, reheating and regeneration |
| C. | Closed cycle gas turbine |
| D. | Open cycle gas turbine with intercooling and reheating |
| Answer» B. Open cycle gas turbine with intercooling, reheating and regeneration | |
| 69. |
Which component of a gas turbine consumes maximum power? |
| A. | Combustion chamber |
| B. | Regenerator |
| C. | Starter |
| D. | Compressor |
| Answer» E. | |
| 70. |
Which of the following is a pressure compounded turbine? |
| A. | Parson's turbine |
| B. | Curtis turbine |
| C. | Rateau turbine |
| D. | All of the above |
| Answer» D. All of the above | |
| 71. |
The continuity equation in compressible fluids is derived on the basis of |
| A. | conservation of velocity head |
| B. | conservation of mass |
| C. | conservation of energy |
| D. | conservation of momentum |
| Answer» C. conservation of energy | |
| 72. |
Most serious energy loss in reaction steam turbine |
| A. | Steam leakage between diaphragm and shaft |
| B. | Impact loss as steam enters moving blades |
| C. | Frictional resistance between steam and nozzle side |
| D. | Leakage over blade ends through radia clearance passages |
| Answer» E. | |
| 73. |
For a jet prepulsion unit, ideally the compressor work and turbine work are |
| A. | unequal |
| B. | equal |
| C. | not related to each other |
| D. | none of the above |
| Answer» C. not related to each other | |
| 74. |
Gas turbine used in aircraft is of |
| A. | closed cycle type with reheating and regeneration and intercooling |
| B. | closed cycle type with reheating |
| C. | open cycle type with reheating, regeneration and intercooling |
| D. | open cycle type |
| Answer» E. | |
| 75. |
Normal standard of compression for rotary compressor is |
| A. | polytropic compression |
| B. | constant pressure compression |
| C. | isentropic compression |
| D. | adiabatic compression |
| Answer» D. adiabatic compression | |
| 76. |
The ratio of actual velocity to the local velocity of sound is called |
| A. | Velocity factor |
| B. | Speed ratio |
| C. | Mach number |
| D. | Velicity ratio |
| Answer» D. Velicity ratio | |
| 77. |
The diverging portion of the nozzle acts as a diffuser for |
| A. | the subsonic flow |
| B. | the supersonic flow |
| C. | both the subsonic as well as supersonic flow |
| D. | none of the above |
| Answer» B. the supersonic flow | |
| 78. |
In a two stage gas turbine plant reheating after first stage |
| A. | increases thermal efficiency |
| B. | decreases thermal efficiency |
| C. | doesoes not affect thermal efficiency |
| D. | none of the above |
| Answer» C. doesoes not affect thermal efficiency | |
| 79. |
Stalling of the blades of axial flow compressor is |
| A. | an unsteady periodic and reversal of flow |
| B. | the fixed mass flow rate regardless of pressure ratio |
| C. | the reduction in lift force at higher angle of incidence |
| D. | none of the above |
| Answer» D. none of the above | |
| 80. |
An axial flow compressor is suitable for |
| A. | low volume flow rates with high pressure rise |
| B. | high volume flow rates with a small pressure rise |
| C. | low volume flow rates with low pressure rise |
| D. | high volume flow rates with high pressure rise |
| Answer» C. low volume flow rates with low pressure rise | |
| 81. |
Which of the following loss in steam turbines is negligible? |
| A. | Residual velocity loss |
| B. | Radiation loss |
| C. | Leakage loss |
| D. | Mechanical friction loss |
| Answer» C. Leakage loss | |
| 82. |
The work ratio of closed cycle gas turbine plant with fixed top temperature of the cycle and fixed pressure ratio rp |
| A. | increases with increase in an inlet temperature to compressor |
| B. | increases with decrease in an inlet temperature to compresor |
| C. | remain same irrespective of inlet temperature to compressor |
| D. | none of the above |
| Answer» C. remain same irrespective of inlet temperature to compressor | |
| 83. |
Gas turbines are taken to |
| A. | the gasoline and diesel engines in its working medium |
| B. | the petrol and diesel engines in its internal combustion |
| C. | the steam turbine in its aspect of steady flow of the working medium |
| D. | All of the above |
| Answer» E. | |
| 84. |
Critical pressure for steam is |
| A. | 185.85 kg/cm2 |
| B. | 245.55 kg/cm2 |
| C. | 225.65 kg/cm2 |
| D. | 212.55 kg/cm2 |
| Answer» D. 212.55 kg/cm2 | |
| 85. |
Which of the following preferred for supercharging of internal combustion engines? |
| A. | Roots blower |
| B. | Reciprocating compressor |
| C. | Sliding vane type compressor |
| D. | Axial flow compressor |
| Answer» B. Reciprocating compressor | |
| 86. |
The source of power for driving a turbocharger is |
| A. | chemical energy of exhaust gases |
| B. | air motor |
| C. | kinetic energy of exhaust gases from the engine |
| D. | electric motor |
| Answer» D. electric motor | |
| 87. |
Actual gas turbine cycle is different from ideal cycle because |
| A. | of internal irreversibility of the process due to friction, turbulence, etc. |
| B. | of variation of specific heats with temperature |
| C. | of losses due to incomplete combustion |
| D. | all of the above |
| Answer» E. | |
| 88. |
In which of the following plant inferior quality fuel can be used? |
| A. | Open cycle gas turbine with regeneration |
| B. | Open cycle gas turbine with intercooling |
| C. | Closed cycle gas turbine |
| D. | Open cycle gas turbine with reheating and regeneration |
| Answer» D. Open cycle gas turbine with reheating and regeneration | |