MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 197 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The m.e.p. of a diesel cycle having fixed compression ratio with increase in cut-off will_________________? |
| A. | increase |
| B. | decreae |
| C. | be unaffected |
| D. | depend on other factors |
| E. | unpredictable |
| Answer» B. decreae | |
| 52. |
The mean effective pressure obtained from engine indicator indicates the________________? |
| A. | maximum pressure developed |
| B. | minimum pressure |
| C. | instantaneous pressure at any instant |
| D. | exhaust pressure |
| E. | average pressure |
| Answer» F. | |
| 53. |
The maximum temperature in the I.C. engine cylinder is of the order of ________________? |
| A. | 500- 1000°C |
| B. | 1000- 1500°C |
| C. | 1500-2000°C |
| D. | 2000-2500°C |
| E. | 2500-3000°C |
| Answer» E. 2500-3000°C | |
| 54. |
The magneto in an automobile is basically__________________? |
| A. | transformer |
| B. | d.c. generator |
| C. | capacitor |
| D. | magnetic circuit |
| E. | a.c. generator |
| Answer» C. capacitor | |
| 55. |
The knock in diesel engine occurs due to____________________? |
| A. | instantaneous and rapid burning of the first part of the charge |
| B. | instantaneous atuo iginition of last part of charge |
| C. | delayed burning of the first part of the charge |
| D. | reduction of delay period |
| E. | all ot the above |
| Answer» B. instantaneous atuo iginition of last part of charge | |
| 56. |
The knocking in diesel engines for given fuel, will be__________________? |
| A. | enhanced by increasing compression ratio |
| B. | enhanced by decreasing compression ratio |
| C. | unaflected by compression ratio |
| D. | first enhanced by increasig compression ratio upto a limit beyond which it will be suppressed |
| E. | dependent on other factors |
| Answer» C. unaflected by compression ratio | |
| 57. |
The inlet value of a four stroke cycle I.C engine remains open for nearly___________________? |
| A. | 180° |
| B. | 125° |
| C. | 235° |
| D. | 200° |
| E. | 275 |
| Answer» D. 200° | |
| 58. |
The ignition of charge by some hot surface in the engine cylinder before operation of spark plug is known as________________? |
| A. | auto ignition |
| B. | preignition |
| C. | retarded ignition |
| D. | accelerated ignition |
| E. | detonation |
| Answer» C. retarded ignition | |
| 59. |
The ignition coil in diesel engines produces voltage of the order of________________? |
| A. | 6 to 12 volts |
| B. | 240 volts |
| C. | 1000 volts |
| D. | 20,000 volts |
| E. | 80,000 volts |
| Answer» E. 80,000 volts | |
| 60. |
The function of a fuel pump in a petrol pump is to______________________? |
| A. | inject fuel in cylinder |
| B. | supply fuel when carburettor fails |
| C. | pump fuel so that it reaches carburettor (to improve thermal efficiency) |
| D. | does not exist |
| Answer» D. does not exist | |
| 61. |
The function of a distributor in an automobile is to__________________? |
| A. | distribute charge, equally to all the cylinders |
| B. | regulate power |
| C. | feed lub oil to all moving parts |
| D. | time the spark |
| E. | inject fuel at appropriate time |
| Answer» E. inject fuel at appropriate time | |
| 62. |
The fuel in diesel engine is normally injected at pressure of_________________? |
| A. | 5-10 kg/cm2 |
| B. | 20-25 kg/cm2 |
| C. | 60-80 kg/cm2 |
| D. | 90-130 kg/cm2 |
| E. | 150-250 kg/cm2 |
| Answer» E. 150-250 kg/cm2 | |
| 63. |
The fuel air ratio in a petrol engine fitted with suction carburettor, operating with dirty air filter as compared to clean filter will be________________? |
| A. | higher |
| B. | lower |
| C. | remain unaffected |
| D. | unpredictable |
| E. | none of the above |
| Answer» B. lower | |
| 64. |
The following volume of air is required for consuming 1 liter of fuel by a four stroke engine_______________? |
| A. | 1 m3 |
| B. | 5 m3 |
| C. | 5-6 m3 |
| D. | 9-10 m3 |
| E. | 15-18 m3 |
| Answer» E. 15-18 m3 | |
| 65. |
The following type of carburettor is preferred_______________? |
| A. | concentric type |
| B. | eccentric type |
| C. | horizontal type |
| D. | vertical type |
| E. | none of the above |
| Answer» B. eccentric type | |
| 66. |
The firing order in a six stroke I.C. engine is_________________? |
| A. | 1-3-6-5-2-4 |
| B. | 1-4-2-5-6-3 |
| C. | 1-6-2-5-4-3 |
| D. | 1-5-2-6-3-4 |
| E. | 1-5-3-4-2-6 |
| Answer» F. | |
| 67. |
The essential equipment for producing high vlotage for sparking in petrol engines with battery is_______________? |
| A. | ignition coil |
| B. | ignition coil and distributor |
| C. | ignition coil and condenser |
| D. | ignition coil and contact breaker |
| E. | ignition coil, contact breaker and con-denser |
| Answer» C. ignition coil and condenser | |
| 68. |
The efficiency of I.C. engines normally is of the order of_________________? |
| A. | 15-20% |
| B. | 20-25% |
| C. | 25-30% |
| D. | 30-35% |
| E. | 35-50% |
| Answer» E. 35-50% | |
| 69. |
The delay period in petrol engine is of the order of__________________? |
| A. | 0.001 sec |
| B. | 0.002 sec |
| C. | 0.01 sec |
| D. | 0.05 sec |
| E. | 0.1 sec |
| Answer» C. 0.01 sec | |
| 70. |
The cooling water requirement for diesel engine is of the order of________________? |
| A. | 0.2 to 1.0 liter per minute per h.p. |
| B. | 1 to 3 liters per minute per h.p. |
| C. | 5 to 10 liters per minute per h.p |
| D. | 10 to 20 liters per minute per h.p. |
| E. | 20-30 liters per minute per h.p |
| Answer» C. 5 to 10 liters per minute per h.p | |
| 71. |
The compression ratio of motor cars is___________________? |
| A. | 5 |
| B. | 7 |
| C. | 10 |
| D. | 13 |
| E. | 16 |
| Answer» C. 10 | |
| 72. |
The cam shaft of a four stroke I.C. engine running at 1500 rmp will run at __________________? |
| A. | 1500 rpm |
| B. | 750 rpm |
| C. | 3000 rpm |
| D. | any value independent of engine speed |
| E. | none of the above |
| Answer» C. 3000 rpm | |
| 73. |
The calorific value of gaseous fuels is expressed in terms of__________________? |
| A. | kcal |
| B. | kcal/kg |
| C. | kcal/m2 |
| D. | kcal/m² |
| E. | all of the above |
| Answer» E. all of the above | |
| 74. |
The basic requirement of a good combustion chamber is___________________? |
| A. | high compression ratio |
| B. | low compression ratio |
| C. | low volumetric efficiency |
| D. | minimum turbulence |
| E. | high power output and high thermal efficiency |
| Answer» F. | |
| 75. |
The ash content in diesel oil should bot be more than_______________? |
| A. | 1% |
| B. | 5% |
| C. | 0.1% |
| D. | 0.01% |
| E. | 0.001% |
| Answer» F. | |
| 76. |
The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is__________________? |
| A. | same |
| B. | less |
| C. | more |
| D. | more or less depending on power rating |
| E. | unpredictable |
| Answer» D. more or less depending on power rating | |
| 77. |
The air requirement of a petrol engine during starting compared to theoretical airequired for complete combustion is___________________? |
| A. | more |
| B. | loss |
| C. | same |
| D. | may be more or less depending on engine capacity |
| E. | unpredictable |
| Answer» C. same | |
| 78. |
The air-fuel ratio of the petrol engine is controlled by__________________? |
| A. | fuel pump |
| B. | governor |
| C. | injector |
| D. | carburettor |
| E. | scavenging |
| Answer» E. scavenging | |
| 79. |
The air-fuel ratio in petrol engines-is controlled by__________________? |
| A. | controlling valve opening/closing |
| B. | governing |
| C. | injection |
| D. | carburettion |
| E. | scavenging and supercharging |
| Answer» E. scavenging and supercharging | |
| 80. |
The actual volume of fresh charge admitted in 4-stroke petrol engine is_________________? |
| A. | equal to stroke volume |
| B. | equal to stroke volume and clearance volume |
| C. | less than stroke volume |
| D. | more than stroke volume |
| E. | more than cylinder volume |
| Answer» D. more than stroke volume | |
| 81. |
The accunmulation of carbon in a cylinder results in increase of________________? |
| A. | clearance volume |
| B. | volumetric efficiency |
| C. | ignition time |
| D. | effective compression ratio |
| E. | valve travel time |
| Answer» E. valve travel time | |
| 82. |
Scavenging is usually done to increase__________________? |
| A. | thermal efficiency |
| B. | speed |
| C. | power output |
| D. | fuel consumption |
| E. | all of the above |
| Answer» D. fuel consumption | |
| 83. |
Scavenging air in diesel engine means___________________? |
| A. | air used for combustion sent under pres-sure |
| B. | forced air for cooling cylinder |
| C. | burnt air containing products of combustion |
| D. | air used for forcing burnt gases out of engine’s cylinder during the exhaust period |
| E. | air fuel mixture |
| Answer» E. air fuel mixture | |
| 84. |
Scavenging air is supplied to a two-stroke engine at a density greater than that of atmosphere. This means the engine is__________________? |
| A. | Supercharged |
| B. | Not supercharged |
| C. | Charged |
| D. | Supercharged provided its speed is low |
| Answer» C. Charged | |
| 85. |
Power impulses from an I.C. engine are somoothed out by__________________? |
| A. | governor |
| B. | crank shaft |
| C. | gear box |
| D. | flywheel |
| E. | timing spark properly |
| Answer» E. timing spark properly | |
| 86. |
Pour point of fuel oil is the_________________? |
| A. | minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in conta |
| B. | temperature at which it solidifies or congeals |
| C. | it catches fire without external aid |
| D. | indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off |
| E. | temperature at which it flows easily |
| Answer» C. it catches fire without external aid | |
| 87. |
Polymerisation is a chemical process in which molecules of a compound become________________? |
| A. | larger |
| B. | slowed down |
| C. | smaller |
| D. | liquid |
| E. | gaseous |
| Answer» B. slowed down | |
| 88. |
Piston rings are plated with chromium,cadmium or phosphate in order to__________________? |
| A. | reduce cost |
| B. | improve surface finish |
| C. | prevent clogging |
| D. | reduce wear and eliminate scuffing |
| E. | improve heat transfer |
| Answer» E. improve heat transfer | |
| 89. |
Piston rings are usually made of___________________? |
| A. | cast iron |
| B. | aluminium |
| C. | phosphor bronze |
| D. | babbitt |
| E. | carbon steel |
| Answer» B. aluminium | |
| 90. |
Pick up the wrong statement? |
| A. | 2-stroke engine can run in any direction |
| B. | In 4-stroke engine, a power stroke is obtained in 4-strokes |
| C. | thermal efficiency of 4-stroke engine is more due to positive scavenging |
| D. | petrol engines work on otto cycle |
| E. | petrol engines occupy more space than diesel engines for same power output |
| Answer» F. | |
| 91. |
Pick up the wrong statement about supercharging __________________? |
| A. | supercharging reduces knocking in diesel engines |
| B. | there can be limited supercharging in petrol engines because of detonation |
| C. | supercharging at high altitudes is essential |
| D. | supercharging results in fuel economy |
| E. | supercharging is essential in aircraft engines |
| Answer» E. supercharging is essential in aircraft engines | |
| 92. |
Pick up the false statement ? |
| A. | Thermal efficiency of diesel engine i about 34% |
| B. | Theoretically correct mixture of air am petrol is approximately 15 : 1 |
| C. | High speed compression engines operate on dual combustion cycle |
| D. | Diesel engines are compression ignition engines |
| E. | S.I. engines are quality-governed engines |
| Answer» F. | |
| 93. |
Pick up false statement? |
| A. | For petrol and large gas engines, quantity governingds preferred |
| B. | In quantity governing, air fuel ratio is almost constant and quantity of charge is changed depending on load |
| C. | In hit and miss governing, fuel supply is completely cut off during one or more number of cycles |
| D. | In quality governing, quantity of fuel is varied to suit the load and total charge of air is varied |
| E. | For close regulation of speed, combination of both quality and quantity governing is used |
| Answer» E. For close regulation of speed, combination of both quality and quantity governing is used | |
| 94. |
Petrol is distilled at a temperature in range of__________________? |
| A. | 30 – 65°C |
| B. | 65 – 220°C |
| C. | 220-350°C |
| D. | 350-450°C |
| E. | 450-550°C |
| Answer» C. 220-350°C | |
| 95. |
Octane number is determined by comparing the performance of the petrol with the following hydrocarbons__________________? |
| A. | iso-octane |
| B. | mixture of normal heptane and iso-oc-tane |
| C. | alpha methyl napthalene |
| D. | mixture of methane and ethane |
| E. | mixture of paraffins and aromatics |
| Answer» C. alpha methyl napthalene | |
| 96. |
Normal heptane_______________? |
| A. | accelerates auto-ignition |
| B. | helps to resist auto-ignition |
| C. | does not affect auto-ignition |
| D. | has no relation with auto-ighition |
| E. | retards auto-ignition |
| Answer» C. does not affect auto-ignition | |
| 97. |
Most high speed compression engines operate on ___________________? |
| A. | Otto cycle |
| B. | Diesel cycle |
| C. | Dual cycle |
| D. | Carnot cycle |
| E. | Two stroke cycle |
| Answer» D. Carnot cycle | |
| 98. |
Most high speed compression engines operate on __________________? |
| A. | Diesel cycle |
| B. | Otto cycle |
| C. | Dual combustion cycle |
| D. | Special type of air cycle |
| E. | Carnot cycle |
| Answer» D. Special type of air cycle | |
| 99. |
Method of governing used in diesel engine is__________________? |
| A. | quantity governing |
| B. | quality governing |
| C. | combined governing |
| D. | partial governing |
| E. | nit and miss governing |
| Answer» C. combined governing | |
| 100. |
Method of governing used in petrol engine is________________? |
| A. | quantity governing |
| B. | quality governing |
| C. | combined governing |
| D. | partial governing |
| E. | hit and miss governing |
| Answer» B. quality governing | |