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mechanical engineering MCQs

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

mechanical engineering Mcqs

1. compressors gas turbines and jet engines 2. theory of machines 3. nuclear power plants 4. engineering materials 5. strength of materials mechanical engineering 6. thermodynamics 7. heat transfer 8. i c engines 9. steam boilers engines nozzles and turbines 10. engineering mechanics 11. fluid mechanics mechanical engineering 12. production technology 13. machine design 14. hydraulic machines 15. workshop technology 16. refrigeration and air conditioning

1. The compressor capacity with decrease in suction temperature_________________?
0

A. decreases

B. remains unaffected

C. increases upto certain limit and then decreases

D. may increase or decrease depending on compressor capacity

E. increases

2. Which is false statement about air receivers ___________________?
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A. These are used to dampen pulsations ,

B. These act as reservoir to- take care of sudden demands

C. These increase compressor efficiency

D. These knock out some oil and moisture

E. These reduce frequent on/off operation of compressors

3. Isothermal compression efficiency, even when running at high speed, can be approached by using A. multi-stage compression B. cold water spray C. both A. and B. above D. fully insulating the cylinder E. high stroke_________________?
0

A. thermal compression efficiency, even when running at high speed, can be approached by using

B. multi-stage compression

C. cold water spray

D. both A. and B. above

E. fully insulating the cylinder

F. high stroke

4. What will be the volume of air at 327C if its volume at 27C is 1.5 m3/mt ?
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A. 18 m3/mt

B. 1.5 m3/mt

C. 0.75 m3/mt

D. 3 m3/mt

E. 6 m3/mt

5. For pipes, laminar flow occurs when Roynolds number is__________________?
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A. less than 4000

B. none of the above

C. between 2000 and 4000

D. less than 2000

E. more than 4000

6. After-cooler is used to__________________?
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A. cause moisture and oil vapour to drop out

B. cool the air

C. reduce volume

D. decrease the delivery temperature for ease in handling

E. increase pressure

7. Inter cooling in compressors__________________?
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A. is the standard practice for big compressors

B. prevents compressor jacket running very hot

C. cools the delivered air

D. results in saving of power in compressing a given volume to given pressure

E. enables compression in two stages

8. Reciprocating air compressor is best suited for___________________?
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A. large quantity of air at high pressure

B. large quantity of air at low pressure

C. small quantity of air at low pressure

D. any one of the above

E. small quantity of air at high pressure

9. Ratio of indicated H.P. and brake H.P. is known as_________________?
0

A. volumetric efficiency

B. adiabatic efficiency

C. relative efficiency

D. mechanical efficiency

E. isothermal efficiency

10. If three forces acting in different planes can be represented by a triangle, these will be in________________?
0

A. none of the above

B. unpredictable

C. partial equilibrium

D. full equilibrium

E. non-equilibrium

11. The ratio of work doen per cycle to the swept volume in case of compressor is called ______________?
0

A. mean effective pressure

B. compression index

C. compressor effectiveness

D. compressor efficiency

E. compression ratio

12. Which of the following is not the unit of power ?
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A. hp (horse power)

B. kcal/kg sec

C. kW (kilowatt)

D. kg m/sec

E. kcal/sec

13. Volumetric efficiency of a compressor without clearance volume________________?
0

A. unpredictable

B. is not dependent upon compressin ratio

C. may increase/decrease depending on compressor capacity

D. decreases with increase in compression ratio

E. increases with increase in compression ratio

14. If two equal forces of magnitude P act at an angle 9, their resultant will be________________?
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A. 2P tan 9/2

B. Psin 9/2

C. IP cos 9/2

D. P/2 cos 9/2

E. IP sin 9/2

15. Metacentre is the point of intersection of _________________________?
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A. buoyant force and the center line of body

B. none of the above

C. all of the above

D. mid point between e.g. and center of buoyancy

E. vertical upward force through e.g. of body and center line of body

16. Clearance volume in actual reciprocating compressors is essential __________________?
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A. to accommedate Valves in the cylinder head

B. to avoid mechanical bang of piston with cylinder head

C. to provide cushioning effect

D. to attain high volumetric efficiency

E. to provide cushioning effect and also to avoid mechanical bang of piston with cylinder head

17. Which of the following is the unit of kinematic viscosity _________________?
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A. poise

B. stoke

C. pascal

D. faraday

E. none of the above

18. Volumetric efficiency of a compressor with clearance volume ________________?
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A. decreases with increase in compression ratio

B. in not dependent upon compression ratio

C. increases with increase in compression ratio

D. unpredictable

E. may increase/decrease depending on compressor capacity

19. A pair of smiths tongs is an example of the lever of__________________?
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A. third order

B. second order

C. first order

D. zeioth order

E. fourth order

20. Which is false statement about multistage compression ?
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A. Outlet temperature is reduced

B. Power consumption per unit of air delivered is low

C. It is best suited for compression ratios around 7:1

D. Volumetric efficiency is high

E. The moisture in air is condensed in the intercooler

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