

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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