MCQOPTIONS
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MCQOPTIONS
This section includes 286 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.
| 51. |
An atom bomb utilises uncontrolled nuclear fission. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 52. |
The thermal efficiency of petrol and gas engines is about |
| A. | 15% |
| B. | 30% |
| C. | 50% |
| D. | 70% |
| Answer» C. 50% | |
| 53. |
The spark ignition engines are governed by |
| A. | hit and miss governing |
| B. | qualitative governing |
| C. | quantitative governing |
| D. | combination of (b) and (c) |
| Answer» D. combination of (b) and (c) | |
| 54. |
The specific fuel consumption per B.P. hour for a petrol engine is about |
| A. | 0.2 kg |
| B. | 0.25 kg |
| C. | 0.3 kg |
| D. | 0.35 kg |
| Answer» C. 0.3 kg | |
| 55. |
In a four stroke cycle diesel engine, the compression |
| A. | starts at 40° after bottom dead centre and ends at 10° before top dead centre |
| B. | starts at 40° before top dead centre and ends at 40° after top dead centre |
| C. | starts at top dead centre and ends at 40° before bottom dead centre |
| D. | may start and end anywhere |
| Answer» B. starts at 40° before top dead centre and ends at 40° after top dead centre | |
| 56. |
Special reactors, called breeder reactors, supply a net gain of fissionable material. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 57. |
The petrol engines are also known as __________ engines. |
| A. | compression ignition |
| B. | spark ignition |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 58. |
The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to |
| A. | inject fuel in a chamber of high pressure at the end of compression stroke |
| B. | inject fuel at a high velocity to facilitate atomisation |
| C. | ensure that penetration is not high |
| D. | all of the above |
| Answer» E. | |
| 59. |
The ignition quality of petrol is expressed by |
| A. | cetane number |
| B. | octane number |
| C. | calorific value |
| D. | all of these |
| Answer» C. calorific value | |
| 60. |
A reactor capable of converting a fertile material into fissile isotopes is called regenerative reactor. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» B. No | |
| 61. |
The sensing element in the control system of nuclear reactors measure the __________ of the neutron flux in the reactor. |
| A. | temperature |
| B. | volume |
| C. | density |
| D. | none of these |
| Answer» D. none of these | |
| 62. |
A fuel will detonate less if it has higher self ignition temperature. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 63. |
Which of the following fuel detonates readily ? |
| A. | Benzene |
| B. | Iso-octane |
| C. | Normal heptane |
| D. | Alcohol |
| Answer» D. Alcohol | |
| 64. |
The method of determination of indicated power of a multi cylinder spark ignition engine is by the use of |
| A. | Morse test |
| B. | prony brake test |
| C. | motoring test |
| D. | heat balance test |
| Answer» B. prony brake test | |
| 65. |
The brake power is always greater than indicated power. |
| A. | Agree |
| B. | Disagree |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 66. |
A diesel engine is __________ as compared to petrol engine, both running at rated load. |
| A. | equally efficient |
| B. | less efficient |
| C. | more efficient |
| D. | None of these |
| Answer» D. None of these | |
| 67. |
In natural uranium, the constituents of three naturally occuring isotopes are |
| A. | U234 = 0.006%, U235 = 0.712% and U238 = 99.282% |
| B. | U234 = 0.712%, U235 = 0.006% and U238 = 99.282% |
| C. | U234 = 99.282%, U235 = 0.006% and U238 = 0.712% |
| D. | U234 = 0.006%, U235 = 99.282% and U238 = 0.712% |
| Answer» B. U234 = 0.712%, U235 = 0.006% and U238 = 99.282% | |
| 68. |
In an internal combustion engine, the process of removing the burnt gases from the combustion chamber of the engine cylinder is known as |
| A. | scavenging |
| B. | detonation |
| C. | supercharging |
| D. | polymerisation |
| Answer» B. detonation | |
| 69. |
The colour of exhaust from diesel engine is generally |
| A. | white |
| B. | bluish |
| C. | black |
| D. | violent |
| Answer» D. violent | |
| 70. |
The engines in which the combustion of fuel takes place inside the engine cylinder are called internal combustion engines. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 71. |
Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine ? |
| A. | inlet valve closing after bottom dead centre |
| B. | inlet valve closing before bottom dead centre |
| C. | inlet valve opening before top dead centre |
| D. | exhaust valve closing after top dead centre |
| Answer» C. inlet valve opening before top dead centre | |
| 72. |
In a coil ignition system of petrol engines, a condenser is connected across the contact-breaker in order to |
| A. | prevent sparking across the gap between the points |
| B. | cause more rapid break of the primary current, giving a higher voltage in the secondary circuit |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 73. |
In a two stroke engine, the working cycle is completed in two revolutions of the crankshaft. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 74. |
The two reference fuels used for cetane rating are |
| A. | cetane and iso-octane |
| B. | cetane and alpha-methyl naphthalene |
| C. | cetane and normal heptane |
| D. | cetane and tetra ethyl lead |
| Answer» C. cetane and normal heptane | |
| 75. |
The ratio of the indicated thermal efficiency to the air standard efficiency is known as |
| A. | mechanical efficiency |
| B. | overall efficiency |
| C. | volumetric efficiency |
| D. | relative efficiency |
| Answer» E. | |
| 76. |
A turbo-jet does not require a turbine to drive the compressor. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 77. |
The air-fuel ratio of the petrol engine is controlled by |
| A. | carburettor |
| B. | injector |
| C. | governor |
| D. | none of these |
| Answer» B. injector | |
| 78. |
The thermodynamic cycle on which the petrol engine works, is |
| A. | Otto cycle |
| B. | Joule cycle |
| C. | Rankine cycle |
| D. | Stirling cycle |
| Answer» B. Joule cycle | |
| 79. |
The firing order in an I.C. engine depends upon |
| A. | arrangement of the cylinders |
| B. | design of crankshaft |
| C. | number of cylinders |
| D. | all of these |
| Answer» E. | |
| 80. |
By higher octane number of spark ignition fuel, it is meant that the fuel has |
| A. | higher heating value |
| B. | higher flash point |
| C. | lower volatility |
| D. | longer ignition delay |
| Answer» E. | |
| 81. |
A moderator, apart from its high neutron slowing power, and low non-productive neutron, should be |
| A. | stable under nuclear radiation |
| B. | corrossion resistant |
| C. | good thermal conductor |
| D. | all of these |
| Answer» E. | |
| 82. |
The brake power is the power available |
| A. | in the engine cylinder |
| B. | at the crank shaft |
| C. | at the crank pin |
| D. | none of these |
| Answer» C. at the crank pin | |
| 83. |
The nuclear radiators produced in a reactor which must be sheilded are |
| A. | electrons |
| B. | α, β and γ rays |
| C. | neutron and gamma rays |
| D. | none of these |
| Answer» D. none of these | |
| 84. |
The specific fuel consumption per B.P. hour for a diesel engine is about |
| A. | 0.2 kg |
| B. | 0.25 kg |
| C. | 0.3 kg |
| D. | 0.35 kg |
| Answer» B. 0.25 kg | |
| 85. |
The thermal efficiency of a petrol engine is __________ as compared to diesel engine. |
| A. | same |
| B. | less |
| C. | more |
| D. | None of these |
| Answer» C. more | |
| 86. |
Number of working strokes per min. for a two stroke cycle engine are __________ the speed of the engine in r.p.m. |
| A. | equal to |
| B. | one-half |
| C. | twice |
| D. | four-times |
| Answer» B. one-half | |
| 87. |
The knocking in diesel engines may be prevented by |
| A. | reducing the delay period |
| B. | raising the compression ratio |
| C. | increasing the inlet pressure of air |
| D. | all of these |
| Answer» E. | |
| 88. |
During idling, a petrol engine requires __________ mixture. |
| A. | lean |
| B. | rich |
| C. | chemically correct |
| D. | None of these |
| Answer» C. chemically correct | |
| 89. |
The compression ignition engines are governed by |
| A. | hit and miss governing |
| B. | qualitative governing |
| C. | quantitative governing |
| D. | combination of (b) and (c) |
| Answer» C. quantitative governing | |
| 90. |
The air standard efficiency of an I.C. engine depends on |
| A. | fuel used |
| B. | speed of engine |
| C. | compression ratio |
| D. | none of these |
| Answer» D. none of these | |
| 91. |
In petrol engines, advancing of the spark timing will __________ the knocking tendency. |
| A. | not effect |
| B. | decrease |
| C. | increase |
| D. | None of these |
| Answer» D. None of these | |
| 92. |
The frictional power (F.P.) is given by |
| A. | F.P. = B.P. - I.P. |
| B. | F.P. = I.P. - B.P. |
| C. | F.P. = B.P./I.P. |
| D. | F.P. = I.P./B.P. |
| Answer» C. F.P. = B.P./I.P. | |
| 93. |
A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of |
| A. | 75% iso-octane and 25% normal heptane |
| B. | 75% normal heptane and 25% iso-octane |
| C. | 75% petrol and 25% diesel |
| D. | 75% diesel and 25% petrol |
| Answer» B. 75% normal heptane and 25% iso-octane | |
| 94. |
The mechanical efficiency (ηm) of the engine is given by |
| A. | ηm = B.P/I.P |
| B. | ηm = I.P/B.P |
| C. | ηm = (B.P × I.P)/100 |
| D. | none of these |
| Answer» B. ηm = I.P/B.P | |
| 95. |
The indicated mean effective pressure of an engine is obtained from the indicator diagram drawn with the help of an engine indicator. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 96. |
Which of the following does not relate to a spark ignition engine ? |
| A. | Ignition coil |
| B. | Spar kplug |
| C. | Carburettor |
| D. | Fuel injector |
| Answer» E. | |
| 97. |
In a four stroke cycle diesel engine, the exhaust valve |
| A. | opens at 30° before bottom dead cnetre and closes at 10° after top dead centre |
| B. | opens at 30° after bottom dead centre and closes at 10° before top dead centre |
| C. | opens at bottom dead centre and closes at top dead centre |
| D. | may open and close anywhere |
| Answer» B. opens at 30° after bottom dead centre and closes at 10° before top dead centre | |
| 98. |
The correct sequence of the decreasing order of brake thermal efficiency of the three given basic types of engines is |
| A. | four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine |
| B. | four stroke S.I. engine, four stroke C.I. engine, two stroke S.I. engine |
| C. | four stroke C.I. engine, two stroke S.I. engine, four stroke S.I. engine |
| D. | two stroke S.I. engine, four stroke S.I. engine, four stroke C.I. engine |
| Answer» B. four stroke S.I. engine, four stroke C.I. engine, two stroke S.I. engine | |
| 99. |
A moderator |
| A. | absorbs neutrons |
| B. | does not absorb neutrons |
| C. | accelerates neutrons |
| D. | none of these |
| Answer» C. accelerates neutrons | |
| 100. |
A gas engine has a swept volume of 300 cm³ and clearance volume of 25 cm³. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is |
| A. | 248 cm³ |
| B. | 252 cm³ |
| C. | 264 cm³ |
| D. | 286 cm³ |
| Answer» D. 286 cm³ | |