McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 51. |
A petrol engine as compared to diesel engine (both running at full load) is |
| A. | More efficient |
| B. | Less efficient |
| C. | Equally efficient |
| D. | Depend on other factors |
| E. | None of the above |
| Answer» B. Less efficient | |
| 52. |
Which one of the following assumptions is not involved while deriving relation for air standard efficiency of Otto cycle? |
| A. | The engine operates at mederate rpm |
| B. | There is always thermal and chemical equilibrium |
| C. | Expansion and compression are adiabatic |
| D. | There is no chemical reaction inside the engine clinder |
| E. | The working fluid is air for which the specific heats are constant |
| Answer» A. The engine operates at mederate rpm | |
| 53. |
Which of the following needs constant cleaning in a diesel engine? |
| A. | Air only |
| B. | Fuel only |
| C. | Air, fuel and lubricating oil |
| D. | Lubricating oil only |
| E. | Air and fuel only |
| Answer» C. Air, fuel and lubricating oil | |
| 54. |
Bagasse is |
| A. | Fibrous portion of sugarcane left after extracting the juice |
| B. | A variety of coal |
| C. | A fuel consisting of wood etc |
| D. | Same as biogas |
| E. | A kind of rice straw |
| Answer» A. Fibrous portion of sugarcane left after extracting the juice | |
| 55. |
During regenerative feed heating |
| A. | Part of the steam is generated in turbine |
| B. | Condenser is supplied with dry and staturated steam |
| C. | Part of the steam is bled from turbine for feed water heating |
| D. | High pressure steam is used to heat low pressure steam coming out of the turbine after expansion |
| E. | None of the above |
| Answer» C. Part of the steam is bled from turbine for feed water heating | |
| 56. |
A jet engine has |
| A. | Propeller in front |
| B. | Propeller in back |
| C. | No propeller |
| D. | Propeller on the top |
| E. | None of the above |
| Answer» C. No propeller | |
| 57. |
Anti-knock for compression ignition engines is |
| A. | Amyl nitrate |
| B. | Aromatics |
| C. | Hexadecane |
| D. | Tetra ethyl lead |
| E. | Trimethyl pentane |
| Answer» C. Hexadecane | |
| 58. |
Which statement is incorrect? |
| A. | LH.P of engines can be determined by more test |
| B. | Morse test can be conducted only on multicylinder engines |
| C. | Morse test can be conducted on petrol engines |
| D. | Morse test can be conducted on CFR engine. |
| E. | Morse test can also be conducted on diesel engines |
| Answer» D. Morse test can be conducted on CFR engine. | |
| 59. |
Advantage of a diesel engine over petrol engine is |
| A. | Low fuel consumption at full load as well as part load |
| B. | Smooth operation at all speeds |
| C. | Low compression ratio |
| D. | No detonation problems |
| E. | All of the above |
| Answer» A. Low fuel consumption at full load as well as part load | |
| 60. |
Forced circulation of water does not take place in which of the following boiler? |
| A. | Benson boiler |
| B. | La Mont boiler |
| C. | Babcock and Wilcox boiler |
| D. | Lancashire boiler |
| E. | Velox boiler |
| Answer» D. Lancashire boiler | |
| 61. |
In multistage compression, perfect intercooling means |
| A. | Temperature of air at inlet to subsequent stages is equal to initial temperature |
| B. | Temperature of air at inlet to subsequent stages is less than initial temperature |
| C. | Temperature of air at inlet to subsequent stages should be zero |
| D. | Temperature of inlet to subsequent stages should be equal to the final temperature |
| E. | None of the above |
| Answer» A. Temperature of air at inlet to subsequent stages is equal to initial temperature | |
| 62. |
The battery used in vespa scooter is |
| A. | No battery is used in the scooters |
| B. | Dry-cell type |
| C. | Lead acid type |
| D. | Nickel-iron type |
| E. | Nickel cadmium type |
| Answer» A. No battery is used in the scooters | |
| 63. |
Which variety of coal has low calorific value? |
| A. | Steam coal |
| B. | Bituminous coal |
| C. | Lignite |
| D. | Anthracite |
| E. | None of the above |
| Answer» C. Lignite | |
| 64. |
Stoichiometric ratio is |
| A. | Chemically correct air-fuel ratio by volume |
| B. | Chemically correct air-fuel ratio by weight |
| C. | Theoretical mixture of air for complete combustion |
| D. | Actual ratio of air to fuel for maximum efficiency |
| E. | None of the above |
| Answer» B. Chemically correct air-fuel ratio by weight | |
| 65. |
Hot spots are |
| A. | Defects in S.I.engines |
| B. | Hottest point within engine cylinder |
| C. | Do not exist in engines |
| D. | The spots where heavier fractions of fuel are vaporised |
| E. | The hottest spots in engines |
| Answer» D. The spots where heavier fractions of fuel are vaporised | |
| 66. |
Air required for complete combustion of 1 kg of carbon is 11.6 kg. If a fuel contains 88.6% Carbon and 11.4% Hydrogen, the air requirement will |
| A. | Will decrease |
| B. | 12 kg |
| D. | Will increase |
| E. | Remain unaltered |
| Answer» D. Will increase | |
| 67. |
Volumetric efficiency of a well designed engine may be in the range |
| A. | 40 to 50 percent |
| B. | 50 to 75 percent |
| C. | 75 to 90 percent |
| D. | Below 40 percent |
| E. | Below 20 percent |
| Answer» C. 75 to 90 percent | |
| 68. |
If the boiler chimney emission consists of dense white smoke, then it can be concluded that |
| A. | Coal contains high percentage of sulphur |
| B. | Insufficient air has been supplied for combustion |
| C. | Chemically correct air has been supplied for combustion |
| D. | Excess air has been supplied for combustion |
| E. | Coal contains high percentage of ash |
| Answer» B. Insufficient air has been supplied for combustion | |
| 69. |
Compression ratio in case of gas engines waries in the range |
| A. | 10 to 15 |
| B. | 5 to 10 |
| C. | 24 to 30 |
| D. | 20 to 24 |
| E. | 15 to 20 |
| Answer» B. 5 to 10 | |
| 70. |
A back pressure generally operates on pressures in the range |
| A. | 150 - 200 kg/cm2 |
| B. | 15 - 40 kg/cm2 |
| C. | 100 - 150 kg/cm2 |
| D. | 50 - 100 kg/cm2 |
| E. | 200 - 350 kg/cm2 |
| Answer» B. 15 - 40 kg/cm2 | |
| 71. |
In automobiles as the speed of vehicle increases the back pressure |
| A. | Increases |
| B. | Reduces |
| C. | Remains unaffected |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» D. Depends on other factors | |
| 72. |
A mechanical indicator is used to determine |
| A. | Pumping horse power |
| B. | Indicated horse power |
| C. | IHP - BHP |
| D. | Friction horse power |
| E. | Brake horse power |
| Answer» B. Indicated horse power | |
| 73. |
During adiabatic compression |
| A. | No heat leaves or enters the system |
| B. | Maximum work is done |
| C. | Specific heat remains constant |
| D. | Temperature remains constant |
| E. | None of the above |
| Answer» A. No heat leaves or enters the system | |
| 74. |
Safety valve generally used on high pressure boiler is |
| A. | Dead weight type |
| B. | Lever type |
| C. | Combination lever and spring type |
| D. | Spring type |
| E. | None of the above |
| Answer» D. Spring type | |
| 75. |
Which of the following engine indicator has least inertia effects? |
| A. | Mechanical indicator |
| B. | Farnborough indicator |
| C. | CRO engine indicator |
| D. | All of the above |
| E. | Carbon dioxide |
| Answer» C. CRO engine indicator | |
| 76. |
Calorific value of methane gas can be determined by |
| A. | Bomb calorimeter |
| B. | Bunsen's apparatus |
| C. | Orsat's apparatus |
| D. | None of the above |
| E. | At constant temperature |
| Answer» D. None of the above | |
| 77. |
Which one of the following factors will not assist in improving thermal efficiency of a compression ignition engine? |
| A. | Fine atomisation and even distribution of fuel |
| B. | Minimum heat loss during combustion |
| C. | Clear exhaust |
| D. | High surface to volume ratio |
| E. | Any of the above |
| Answer» D. High surface to volume ratio | |
| 78. |
A diesel power plant is best suited as |
| A. | Base load plant |
| B. | Stand by plant |
| C. | Peak load plant |
| D. | General purpose plant |
| E. | None of the above |
| Answer» B. Stand by plant | |
| 79. |
Excessive moisture in steam in a steam turbine is likely to result in |
| A. | Erosion of turbine blades |
| B. | Excess work done by rotor due to momentum of water particles |
| C. | Overheating of turbine blaces |
| D. | Reduced load on condenser |
| E. | Reduced size of steam turbine |
| Answer» A. Erosion of turbine blades | |
| 80. |
According to Boyle's law |
| A. | At constant pressure the temperature of a gas varies inversely as its volume |
| B. | At constant pressure the absolute temperature of a gas varies inversely as its volume |
| C. | At constant temperature, the pressure of a gas varies inversely as its volume |
| D. | At constant temperature, the absolute pressure of a gas varies inversely as its volume |
| E. | None of the above |
| Answer» D. At constant temperature, the absolute pressure of a gas varies inversely as its volume | |
| 81. |
An optical pyrometer works on the principle of |
| A. | Expansion of fluids |
| B. | Mono-chromatic radiation |
| C. | Thermo-electric effect |
| D. | Total radiation |
| E. | Change of electrical resistance |
| Answer» B. Mono-chromatic radiation | |
| 82. |
Air fuel ratio for a jet engine is of the order of |
| A. | 15 ; 1 |
| B. | 20 ; 1 |
| C. | 400 ; 1 |
| D. | 60 ; 1 |
| E. | 10 ; 1 |
| Answer» D. 60 ; 1 | |
| 83. |
The top ring nearest to the piston crown is known as |
| A. | Oil ring |
| B. | Scrapper ring |
| C. | Compression ring |
| D. | Groove ring |
| E. | Any of the above |
| Answer» C. Compression ring | |
| 84. |
The vapour pressure is related to the enthalpy of vaporization in |
| A. | Maxwell's equation |
| B. | Henry's law |
| C. | Dalton's law |
| D. | Clausius Clapeyron equation |
| E. | Raoult's law |
| Answer» D. Clausius Clapeyron equation | |
| 85. |
Flash point of a liquids is the temperature at which |
| A. | The fuel ignites with clearly visible flash |
| B. | Fuel vaporises at the prescribed rate |
| C. | The fuel emits vapours at a rate which produces an inflammable mixture with air |
| D. | The fuel ignites without a park |
| E. | The fuel spontaneously ignites |
| Answer» C. The fuel emits vapours at a rate which produces an inflammable mixture with air | |
| 86. |
According to kinetic theory of heat |
| A. | At absolute zero there is absolutely no vibration of molecules |
| B. | At low temperatures all bodies are in solid state |
| C. | 25 to 30 |
| D. | Temperature should rise during boiling |
| E. | Temperature should fall during freezing |
| Answer» A. At absolute zero there is absolutely no vibration of molecules | |
| 87. |
Regenerative feed heating of steam turbines is done primarily to |
| A. | Improve thermal efficiency of the condenser |
| B. | Increase the expansion range for steam in the turbine |
| C. | Improve overall efficiency of the plant |
| D. | Reduce pressure of steam in exhaust |
| E. | Reduce boiler losses in the gases |
| Answer» C. Improve overall efficiency of the plant | |
| 88. |
Ricardo's theory is associated with |
| A. | Steam turbines |
| B. | Wankel engines |
| C. | Internal combustion engines |
| D. | Closed cycle gas turbines |
| E. | Engine vibrations |
| Answer» C. Internal combustion engines | |
| 89. |
A 'blue' flame is |
| A. | Non-radiant flame |
| B. | Radiant flame |
| C. | Super high temperature flame |
| D. | Ordinary flame in oil burners |
| E. | None of the above |
| Answer» A. Non-radiant flame | |
| 90. |
The thermal efficiency of a dual cycle engine with fixed compression ratio and fixed quantity of het and with increase in pressure ratio, will |
| A. | Increase |
| B. | Decrease |
| C. | Not change |
| D. | Depends on another factors |
| E. | None of the above |
| Answer» A. Increase | |
| 91. |
Turbidity in boiler feed water causes |
| A. | Sludge |
| B. | Embrittlement |
| C. | Corrosion |
| D. | Scale |
| E. | None of the above |
| Answer» A. Sludge | |
| 92. |
A mixture containing 60% cetane and 40% Iso-octane will have |
| A. | Cetane number 60 |
| B. | Cetane number 40 |
| C. | Octane number 60 |
| D. | Octane number 40 |
| E. | None of the above |
| Answer» E. None of the above | |
| 93. |
A vacuum of 712 mm was obtained with the barometer reading 753 mm of mercury. The corrected vacuum to a standard barometer of 760 would be |
| A. | 719 mm Hg |
| B. | 753 mm Hg |
| C. | 706 mm Hg |
| D. | 760 mm Hg |
| E. | 712 mm Hg |
| Answer» A. 719 mm Hg | |
| 94. |
Flash point for diesel fuel oil should be |
| A. | Minimum 49?C |
| B. | Maximum 49?C |
| C. | Maximum 100?C |
| D. | Maximum 200?C |
| E. | None of the above |
| Answer» A. Minimum 49?C | |
| 95. |
The knocking tendency in a compression ignition engine for a given fuel will |
| A. | Enhance by reducing compression ratio |
| B. | Enhance by increasing compression ratio |
| C. | Depend on other factors |
| D. | Increase to certain limits and then no change |
| E. | None of the above |
| Answer» A. Enhance by reducing compression ratio | |
| 96. |
A steam turbine in which a part of the steam turbine after partial expansion is used for process heating and the remaining steam is further expanded for power generation, is known as |
| A. | Impulse turbine |
| B. | Regenerative turbine |
| C. | Back pressure turbine |
| D. | Pass out turbine |
| E. | 50% reaction turbine |
| Answer» D. Pass out turbine | |
| 97. |
A De-Laval turbine is |
| A. | Multiple stage reaction turbine |
| B. | Single rotor impulse turbine |
| C. | Multiple rotor reaction turbine |
| D. | Velocity compounded impulse turbine |
| E. | Single rotor reaction turbine |
| Answer» B. Single rotor impulse turbine | |
| 98. |
In a cut off covered steam engine |
| A. | Admission pressore remains constant while cut off is varied |
| B. | Admission pressure is reduced while cut off remains unaltered |
| C. | Admission pressure and cut off both are varied |
| D. | Neither admission pressure nor cut off is varied |
| E. | Admission pressure is increased while cut off remains unaltered |
| Answer» A. Admission pressore remains constant while cut off is varied | |
| 99. |
Which one of the following is a safety device on a compressor? |
| A. | Intercooler relief valve |
| B. | Over pressure shut down |
| C. | Strainer |
| D. | Over speed shut down |
| E. | Relief valve |
| Answer» E. Relief valve | |
| 100. |
Naphtha is used as |
| A. | Lubricant for turbines |
| B. | Lubricant for slow speed engines |
| C. | Fuel for marine engines |
| D. | Fuel for furnaces |
| E. | Fuel for aero engines |
| Answer» D. Fuel for furnaces | |
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