McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 1. |
Mechanical efficiency is the ratio of |
| A. | brake power to heat input |
| B. | indicated power to heat input |
| C. | brake power to indicated power |
| D. | friction loss to heat input |
| Answer» C. brake power to indicated power | |
| 2. |
Most commonly used lubrication system in automobiles is the |
| A. | splash system |
| B. | pressure system |
| C. | petrol system |
| D. | gravity system |
| Answer» B. pressure system | |
| 3. |
Friction that occurs between the layers of oil film is called |
| A. | viscous friction |
| B. | greasy friction |
| C. | dry friction |
| D. | boundary friction |
| Answer» A. viscous friction | |
| 4. |
Crankcase ventilation, is provided |
| A. | to cool cylinder |
| B. | to cool crankcase |
| C. | to cool piston |
| D. | to remove blow by |
| Answer» D. to remove blow by | |
| 5. |
the most important property of the lubricant is |
| A. | density |
| B. | viscosity |
| C. | thermal conductivity |
| D. | none of the above |
| Answer» B. viscosity | |
| 6. |
The maximum pressure in the lubrication system is controlled by |
| A. | oil pump |
| B. | oil filter |
| C. | valve relief |
| D. | supply voltage |
| Answer» C. valve relief | |
| 7. |
The lubricants commonly used in the automobiles are |
| A. | animal oils |
| B. | vegetable oils |
| C. | mineral oils |
| D. | cooking oils |
| Answer» B. vegetable oils | |
| 8. |
Detergents are oil additives used to |
| A. | reduce viscosity |
| B. | increase fire point |
| C. | prevent sludge formation |
| D. | prevent foaming |
| Answer» C. prevent sludge formation | |
| 9. |
Oil pressure in the dry sump lubrication system is around |
| A. | 5 bar - 10 bar |
| B. | 11 bar 15 bar |
| C. | 3 bar - 8 bar |
| D. | 1 bar |
| Answer» C. 3 bar - 8 bar | |
| 10. |
For mep decreases when using |
| A. | single cylinder engine |
| B. | smaller number of larger cylinders |
| C. | larger number of smaller cylinders |
| D. | none of the above |
| Answer» C. larger number of smaller cylinders | |
| 11. |
With increase in compression ratio, mechanical efficiency |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | compression ratio has nothing to do with ƞmech |
| Answer» A. increases | |
| 12. |
Blow by losses are |
| A. | directly proportional to the inlet pressure |
| B. | inversely proportional to the inlet pressure |
| C. | proportional to the square root of inlet pressure |
| D. | none of the above |
| Answer» C. proportional to the square root of inlet pressure | |
| 13. |
Mist lubrication system is mainly used in |
| A. | four-stroke petrol engine |
| B. | four-stroke diesel engine |
| C. | two-stroke petrol engine |
| D. | Wankle engine |
| Answer» C. two-stroke petrol engine | |
| 14. |
Additives are added in lubricant to have |
| A. | detergent-dispersant characteristics |
| B. | pour point depression |
| C. | antifoam characteristics |
| D. | all of the above |
| Answer» D. all of the above | |
| 15. |
The principal surfaces requiring lubrication in an IC engine are |
| A. | cylinder head |
| B. | crankcase |
| C. | inlet and exhaust manifold |
| D. | none of the above |
| Answer» D. none of the above | |
| 16. |
The heat given to cooling medium in IC engines is about |
| A. | 50-60% |
| B. | 30-40% |
| C. | 10-20% |
| D. | 60-70% |
| Answer» B. 30-40% | |
| 17. |
Radiator is provided to |
| A. | cool the jacket water |
| B. | pressurise the cooling water |
| C. | provide additional water flow |
| D. | none of the above |
| Answer» A. cool the jacket water | |
| 18. |
Thermostat is used in radiators to |
| A. | control the velocity of water |
| B. | control distribution of water to various cylinders |
| C. | control the water temperature |
| D. | control the pressure of water |
| Answer» C. control the water temperature | |
| 19. |
As the compression ratio increases, there is a |
| A. | large increase in heat rejection |
| B. | large decrease in heat reduction |
| C. | marginal increase in heat rejection |
| D. | marginal reduction in heat rejection |
| Answer» D. marginal reduction in heat rejection | |
| 20. |
Spark timing other than minimum spark advance for best torque (MBT) results in |
| A. | less heat rejection |
| B. | more beat rejection |
| C. | no effect on heat rejection |
| D. | none of the above |
| Answer» B. more beat rejection | |
| 21. |
Direct system of cooling air is one which |
| A. | cooling water flows by gravity |
| B. | hot water is continuously cooled and circulated |
| C. | hot water is simply discharged |
| D. | water is allowed to evaporate in the cylinder jacket |
| Answer» C. hot water is simply discharged | |
| 22. |
In evaporate cooling systems, heat absorbed per kg of coolant air is equal to |
| A. | Cp Δ t |
| B. | Cv Δ t |
| C. | latent heat of the coolant |
| D. | (Cp – Cv) Δ t |
| Answer» C. latent heat of the coolant | |
| 23. |
Pump used in the forced cooling system is normally |
| A. | piston pump |
| B. | gear pump |
| C. | vane pump |
| D. | centrifugal pump |
| Answer» D. centrifugal pump | |
| 24. |
Limitations of air cooling systems are |
| A. | applicable only to large engines |
| B. | cooling is fast |
| C. | higher working temperature compared to water cooling |
| D. | all of the above |
| Answer» C. higher working temperature compared to water cooling | |
| 25. |
Which is more viscous lib oil |
| A. | SEA 30 |
| B. | SAE 40 |
| C. | SAE 50 |
| D. | SAE 80. |
| Answer» D. SAE 80. | |
| 26. |
In a naturally aspirated diesel engine, the air is supplied by |
| A. | a supercharger |
| B. | a centrifugal blower |
| C. | a vacuum chamber |
| D. | an injection tube |
| Answer» C. a vacuum chamber | |
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