McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 1. |
Advantage of reciprocating IC engines over steam turbine is |
| A. | Mechanical simplicity |
| B. | Improved plant efficiency |
| C. | Lower average temperature |
| D. | all of the above |
| Answer» D. all of the above | |
| 2. |
The intake charge in a diesel engine consists of |
| A. | air alone |
| B. | air + lubricating oil |
| C. | air + fuel |
| D. | air + fuel + lubricating oil |
| Answer» A. air alone | |
| 3. |
Engines of different cylinder dimensions, power and speed can be compared on the basis of |
| A. | Maximum pressure |
| B. | Fuel consumption |
| C. | mean effective pressure |
| D. | unit power |
| Answer» C. mean effective pressure | |
| 4. |
Disadvantages of reciprocating IC engine are |
| A. | vibration |
| B. | use of fossil fuels |
| C. | balancing problems |
| D. | all of the above |
| Answer» D. all of the above | |
| 5. |
Gudgeon pin forms the link between |
| A. | piston and big end of connecting rod |
| B. | piston and small end of connecting rod |
| C. | connecting rod and crank |
| D. | big end and small end |
| Answer» B. piston and small end of connecting rod | |
| 6. |
In a four-stroke IC engine cam shaft rotates at |
| A. | same speed as crankshaft |
| B. | twice the speed of crankshaft |
| C. | halt the speed of crankshaft |
| D. | none of the above |
| Answer» C. halt the speed of crankshaft | |
| 7. |
Thermal efficiency of CI engine is higher than that of SI engine due |
| A. | light weight |
| B. | higher compression ratio |
| C. | constant pressure heat addition |
| D. | none of the above |
| Answer» B. higher compression ratio | |
| 8. |
SI engines are of |
| A. | light weight |
| B. | high speed |
| C. | homogeneous change of fuel and oil |
| D. | all of the above |
| Answer» D. all of the above | |
| 9. |
Compression ratio in diesel engines is of the order of |
| A. | 5-7 |
| B. | 7 -10 |
| C. | 10 – 12 |
| D. | 14-20 |
| Answer» D. 14-20 | |
| 10. |
Main advantage of a two-stroke engine over four-stroke engine is |
| A. | more uniform torque on the crankshaft |
| B. | more power output for the cylinder of same dimensions |
| C. | absence of valves |
| D. | all of the above |
| Answer» D. all of the above | |
| 11. |
Engines used for ships are normally |
| A. | four-stroke Sl engines of very high power |
| B. | two-stroke CI engines of very high power |
| C. | four-stroke Cl engines of high speed |
| D. | two-stroke SI engines of high power |
| Answer» B. two-stroke CI engines of very high power | |
| 12. |
If L is the stroke and N is the rpm, mean piston speed of two-stroke engine |
| A. | LN |
| B. | LN/2 |
| C. | 2LN |
| D. | none of the above |
| Answer» C. 2LN | |
| 13. |
The volumetric efficiency of the SI engine is comparatively |
| A. | lower than CI engine |
| B. | higher than CI engine |
| C. | will be same as CI engine |
| D. | none of the above |
| Answer» A. lower than CI engine | |
| 14. |
Brake specific fuel consumption is defined as |
| A. | fuel consumption per hour |
| B. | fuel consumption per km |
| C. | fuel consumption per BP |
| D. | fuel consumption per brake power hour |
| Answer» D. fuel consumption per brake power hour | |
| 15. |
Engine can be fired with |
| A. | solid fuel |
| B. | liquid fuel |
| C. | gaseous fuel |
| D. | any of the above fuels |
| Answer» D. any of the above fuels | |
| 16. |
A two-stroke engine can be identified by |
| A. | cooling system |
| B. | lubrication system |
| C. | absence of valves |
| D. | piston size |
| Answer» C. absence of valves | |
| 17. |
Advantage of two-stroke engine is |
| A. | more uniform torque |
| B. | lighter flywheel |
| C. | no valves |
| D. | all of the above |
| Answer» D. all of the above | |
| 18. |
Charge pressure at the inlet port of a two-stroke engine is |
| A. | 20 bar |
| B. | vacuum |
| C. | atmospheric |
| D. | higher than atmospheric |
| Answer» D. higher than atmospheric | |
| 19. |
The most perfect method of scavenging is |
| A. | cross scavenging |
| B. | uniflow scavenging |
| C. | loop scavenging |
| D. | reverse flow scavenging |
| Answer» B. uniflow scavenging | |
| 20. |
Two-stroke SI engines suffer from |
| A. | fuel loss |
| B. | idling difficulty |
| C. | both (a) and (b) together |
| D. | none of the above |
| Answer» A. fuel loss | |
| 21. |
At the same speed two-stroke engine of the same size as a four-stroke engine will develop |
| A. | same power |
| B. | half the power |
| C. | twice the power |
| D. | four times the power |
| Answer» C. twice the power | |
| 22. |
Two wheelers without deflector type piston use |
| A. | loop scavenging |
| B. | unifow scavenging |
| C. | reverse flow scavenging |
| D. | cross scavenging |
| Answer» D. cross scavenging | |
| 23. |
Crankcase scavenged engines have delivery ratio of |
| A. | greater than 1 |
| B. | less than 1 |
| C. | equal to 1 |
| D. | none of the above |
| Answer» C. equal to 1 | |
| 24. |
The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft |
| A. | 1/2 |
| B. | 1 |
| C. | 2 |
| D. | 4 |
| Answer» C. 2 | |
| 25. |
In a diesel engine, the fuel is ignited by |
| A. | spark |
| B. | injected fuel |
| C. | heat resulting from compressing air that is supplied for combustion |
| D. | ignitor |
| Answer» C. heat resulting from compressing air that is supplied for combustion | |
| 26. |
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 com-bastion |
| D. | air used for forcing burnt gases out of engine's cylinder during the exhaust period |
| Answer» D. air used for forcing burnt gases out of engine's cylinder during the exhaust period | |
| 27. |
Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged? |
| A. | yes |
| B. | no |
| C. | to some extent |
| D. | unpredictable |
| Answer» B. no | |
| 28. |
The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called |
| A. | net efficiency |
| B. | efficiency ratio |
| C. | relative efficiency |
| D. | overall efficiency |
| Answer» C. relative efficiency | |
| 29. |
Compression ratio of LC. Engines is |
| A. | the ratio of volumes of air in cylinder before compression stroke and after compression stroke |
| B. | volume displaced by piston per stroke and clearance volume in cylinder |
| C. | ratio of pressure after compression and before compression |
| D. | swept volume/cylinder volume |
| Answer» A. the ratio of volumes of air in cylinder before compression stroke and after compression stroke | |
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