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This section includes 315 Mcqs, each offering curated multiple-choice questions to sharpen your Automobile Engineering knowledge and support exam preparation. Choose a topic below to get started.
51. |
If the oil level in the oil pan of the engine is maintained above the gauge mark, the likely damage it may cause is |
A. | Engine fuming |
B. | Carbon deposits |
C. | Blue colour in exhaust |
D. | All of the above |
E. | None of the above |
Answer» E. None of the above | |
52. |
Boiling range of kerosene is |
A. | 50 to 100?C |
B. | 100 to 150?C |
C. | 150 to 300?C |
D. | 350 to 500?C |
E. | None of the above |
Answer» D. 350 to 500?C | |
53. |
The most widely used brakes are operted |
A. | Electrically |
B. | Hydraulically |
C. | By vacuum |
D. | Combination of (A) and (C) |
E. | Mechanical |
Answer» C. By vacuum | |
54. |
In a S.I. engine high air velocity through air hom may be of the order of |
A. | 100 m/s |
B. | 10 m/s |
C. | 1 m/s |
D. | 5 m/s |
E. | 50 m/s |
Answer» B. 10 m/s | |
55. |
Cetane number of Diesel oil normally available in market is in the range. |
A. | 75 -- 80 |
B. | 60 -- 65 |
C. | 90 -- 105 |
D. | 90 -- 100 |
E. | 45 -- 50 |
Answer» F. | |
56. |
Efficiency of an IC engine is normally of the order of |
A. | 30-35% |
B. | 50-60% |
C. | 10-15% |
D. | 80-90% |
E. | Alcohol |
Answer» B. 50-60% | |
57. |
In a four stroke SI engine the inlet valve opens |
A. | at TDC and closes at BDC |
B. | 10? before TDC and closes 10? after BDC |
C. | 10? before TDC and closes 10? after BDC |
D. | 10? before TDC and closes 50? after BDC |
E. | None of the above |
Answer» E. None of the above | |
58. |
Quality of diesel oil can be expressed in terms of cetane number and also |
A. | aniline point |
B. | API gravity |
C. | SAE number |
D. | diesel index |
E. | None of the above |
Answer» C. SAE number | |
59. |
Cetane number of a Diesel fuel is measure of |
A. | Ignition quality |
B. | Viscosity |
C. | Volatility |
D. | Delay period |
E. | A.P.I. specific gravity |
Answer» E. A.P.I. specific gravity | |
60. |
The ignition coil acts as |
A. | A capacitor |
B. | An inductor |
C. | A RC circuit |
D. | A step up transformer |
E. | A step down transformer |
Answer» E. A step down transformer | |
61. |
If a spark plug does not fire, the probable cause could be |
A. | Cracked porcelain |
B. | Carbonized porcelain |
C. | Moisture or dirt accumulation on porcelain |
D. | Weak ignition coil |
E. | Any of the above |
Answer» C. Moisture or dirt accumulation on porcelain | |
62. |
In case of a Petrol engine, the spark plug should produce the spark |
A. | exactly at the end of compression stroke |
B. | slightly before the end of compression stroke |
C. | slightly after the end of exhaust stroke |
D. | none of the above |
E. | None of the above |
Answer» C. slightly after the end of exhaust stroke | |
63. |
In automobile, probable cause for ineffective brakes could be |
A. | Grease on lining |
B. | Excessive lining wear |
C. | Drums scored |
D. | Any of above |
E. | None of the above |
Answer» E. None of the above | |
64. |
High gum content in petrol may result in |
A. | detonation |
B. | misfiring |
C. | clogging of carburettor |
D. | none of the above |
E. | None of the above |
Answer» D. none of the above | |
65. |
In automobile ignition system contact breaker is used for |
A. | Opening and closing the primary circuit |
B. | opening and closing the secondary circuit |
C. | increasing the duration of spark |
D. | increasing the intensity of spark |
E. | None of the above |
Answer» B. opening and closing the secondary circuit | |
66. |
Acid used in automobile battery is |
A. | Hydrochloric acid |
B. | Sulphuric acid |
C. | Dilute nitric acid |
D. | Concentrated nitric acid |
E. | Hydrofluoric acid |
Answer» C. Dilute nitric acid | |
67. |
Which instrument is used to measure specific gravity |
A. | Thermometer |
B. | Hydrometer |
C. | Hydrometer |
D. | Anemometer |
E. | None of the above |
Answer» D. Anemometer | |
68. |
In spark plug the gap between the electrodes is |
A. | 10 mm |
B. | around 5 mm |
C. | around 1 mm |
D. | less than 1 mm |
E. | None of the above |
Answer» E. None of the above | |
69. |
The turbulence in diesel engine ensures to |
A. | Increase the compression pressure |
B. | Reduce the engine vibrations |
C. | Bring the fuel quickly in contact with air |
D. | Increase the fuel consumption |
E. | Increase the volumetric efficiency |
Answer» D. Increase the fuel consumption | |
70. |
In an automobile the probable cause for dragging brakes could be |
A. | Lack of clearance |
B. | Drums out of round |
C. | Loose wheel bearings |
D. | Weak retracting spring |
E. | Any of the above |
Answer» F. | |
71. |
The stationary part of the Wankel engine has an inner contour of |
A. | elliptical section |
B. | two lobed epitrochoid section |
C. | four lobed epitrochoid section |
D. | none of the above |
E. | None of the above |
Answer» C. four lobed epitrochoid section | |
72. |
Executive clutch clearance caused by improper adjustment or wear of sliding sleeve, generally results in |
A. | Clutch slip |
B. | Clutch failure to disengage |
C. | Clutch plate over heating |
D. | Uneven clutch engagement |
E. | Any of the above |
Answer» C. Clutch plate over heating | |
73. |
Diesel engines are generally preferred for road transport these days because of low |
A. | Maintenance cost |
B. | Operating cost |
C. | Initial cost |
D. | Prime cost |
E. | Manufacturing cost |
Answer» C. Initial cost | |
74. |
The device used to measure the clearance between the valve and tappet of an internal combustion engine is |
A. | Slip gauge |
B. | Thickness gauge |
C. | Feeler gauge |
D. | Snap gauge |
E. | Micrometer |
Answer» D. Snap gauge | |
75. |
Which of the following symptoms will not show that the combustion is necessarily complete or not? |
A. | Presence of free carbon in exhaust |
B. | Presence of carbon monoxide in the exhaust |
C. | Presence of oxygen is the exhaust |
D. | Presence of nitrogen in the exhaust |
E. | None of the above |
Answer» E. None of the above | |
76. |
In a 2-stroke S.I. engine |
A. | exhaust and transfer (inlet) ports open and cloe simultaneously |
B. | exhaust port opens 5? before the transfer port and closes 5? after the transfer port |
C. | exhaust port opens 5? ahead of the transfer port but both ports close simultaneously |
D. | none of the above |
E. | None of the above |
Answer» C. exhaust port opens 5? ahead of the transfer port but both ports close simultaneously | |
77. |
The condenser in ignition circuit of an S.I. engine |
A. | increases the battery voltage |
B. | decreases the current from battery |
C. | avoids arcing at contact breaker |
D. | none of the above |
E. | None of the above |
Answer» D. none of the above | |
78. |
When fully charged, the terminal voltage per cell for a battery is |
A. | 1.5 volts |
B. | 2.7 volts |
C. | 1.7 volts |
D. | 6 volts |
E. | 12 volts |
Answer» C. 1.7 volts | |
79. |
The phenomenon that causes pressure waves resulting in vibration of structure, rough running and melting of piston is |
A. | detonation |
B. | pre-ignition |
C. | knocking |
D. | none of the above |
E. | None of the above |
Answer» B. pre-ignition | |
80. |
Over heating of a two stroke air cooled engine cannot be due to |
A. | Incorrect ignition or valve timing |
B. | Too lean fuel mixture |
C. | Lack of cylinder jacket cooling water |
D. | Partly restricted exhaust system |
E. | Restricted air cleaner |
Answer» D. Partly restricted exhaust system | |
81. |
Stratification of charge is achieved by |
A. | use of two or more carburettors |
B. | locating two spark plugs on a cylinder |
C. | incorporating an auxiliary chamber |
D. | combining inlet and exhaust valves into a single unit |
E. | None of the above |
Answer» D. combining inlet and exhaust valves into a single unit | |
82. |
Balls for a ball bearing are made of |
A. | Stainless steel |
B. | Carbon chrome steel |
C. | High speed steel |
D. | Mild steel |
E. | Stainless steel |
Answer» C. High speed steel | |
83. |
The escape of burned gases from the combustion chamber past the pistons and into the crank case is called |
A. | Gas-loss |
B. | Crank case explosion |
C. | By-pass |
D. | Blow-by |
E. | Passed gas |
Answer» E. Passed gas | |
84. |
In order to engage securely and prevent dragging the clearance between release bearing and release collar in a clutch is usually |
A. | 30 - 35 mm |
B. | 20 - 25 mm |
C. | 40 - 50 mm |
D. | 2 - 3 mm |
E. | 10 - 15 mm |
Answer» E. 10 - 15 mm | |
85. |
The efficiency of an oil bath type air cleaner is usually |
A. | 90% |
B. | 50% |
C. | 60% |
D. | 99% |
E. | 80% |
Answer» E. 80% | |
86. |
LPG mainly consists of |
A. | Methane and ethane |
B. | Propane and butane |
C. | Petrol and diesel |
D. | Hexane and butadiene |
E. | None of the above |
Answer» C. Petrol and diesel | |
87. |
In a S.I. engine the intake valve closes |
A. | 35? to 80? after BDC |
B. | 25? to 80? before BDC |
C. | At TdDC |
D. | 10? to 20? before |
E. | At BDC |
Answer» B. 25? to 80? before BDC | |
88. |
For the best utilization of fuel, in the engine cylinder, the air supply should be |
A. | About 10% surplus |
B. | 15 to 20 percent deficient |
C. | About 25% surplus |
D. | 5 to 10 percent deficient |
E. | Chemically correct |
Answer» B. 15 to 20 percent deficient | |
89. |
Which one of the following is a correct statement |
A. | the exhaust valve of a four stoke I.C. engine should open exactly at the end of expansion stroke |
B. | in actual practice, inlet valve of a four stroke I.C. engine should open exactly at the start of suction stroke |
C. | the inlet valve remains open approximately for 180? |
D. | valve overlap is the angle during which both the inlet and exhaust valves remain open simultaneously |
E. | None of the above |
Answer» E. None of the above | |
90. |
In a Diesel engine the duration between the time of injection and the time of ignition is called |
A. | Spil cut off |
B. | Delay period |
C. | Period of injection |
D. | Period of ignition |
E. | None of the above |
Answer» C. Period of injection | |
91. |
A heat-treated glass generally used in automobiles upon cracking bursts into |
A. | Sharp edged fragments |
B. | Small particles |
C. | Does not disintegrate |
D. | Either of the above |
E. | None of the above |
Answer» C. Does not disintegrate | |
92. |
The function of Diesel feed pump (when ever provided) is to |
A. | Pump the fuel to the injector |
B. | Pump the fuel from the tank into the injection pump |
C. | Send back the fuel from the injector into the tank |
D. | Pump the oil into the main gallery |
E. | Pump the fuel from the injection pump to the injector |
Answer» C. Send back the fuel from the injector into the tank | |
93. |
Clutch slippage while clutch is engaged is particularly noticeable |
A. | During acceleration |
B. | At low speed |
C. | While starting the engine |
D. | During idling |
E. | During braking |
Answer» B. At low speed | |
94. |
Circumferential grooves on tyres |
A. | Lessen the danger of skidding |
B. | Increase load carrying capacity |
C. | Provide good traction |
D. | Remove any stones etc. from sticking to the tyre |
E. | All of the above |
Answer» B. Increase load carrying capacity | |
95. |
The knocking in S.I. engines can be prevented if the end mixture is having |
A. | high density |
B. | medium density |
C. | low density |
D. | none of the above |
E. | None of the above |
Answer» D. none of the above | |
96. |
Bead of a tyre constitutes |
A. | metal foundations of the tyre |
B. | side walls of the tyre |
C. | shoulder region |
D. | none of the above |
E. | None of the above |
Answer» B. side walls of the tyre | |
97. |
When not in use, the self-discharge of an automobile battery in dry weather is usually |
A. | 0.5 to 1% |
B. | 7 to 7.5% |
C. | Not more than 10% |
D. | Not more than 15% |
E. | Any of the above |
Answer» B. 7 to 7.5% | |
98. |
Dirt or gum in fuel nozzle or jets may cause |
A. | Excessive fuel consumption |
B. | Uneven engine speed |
C. | Smoky black exhaust |
D. | Lack of engine power |
E. | White exhaust |
Answer» D. Lack of engine power | |
99. |
A thermostat is provided in automobile engines for |
A. | Controlling the temperature of the piston |
B. | Regulating the temperature of lubricating oil |
C. | Regulating the temperature of suction air |
D. | Regulating the temperature of haust gases. |
E. | Controlling the temperature of the cooling system |
Answer» F. | |
100. |
The probable cause for uneven wear of tyres for a truck could be |
A. | Low tyre pressure |
B. | Excessive camber |
C. | Tyres overloaded |
D. | Incorrect castor |
E. | Any of the above |
Answer» F. | |