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machine design MCQs

Practise focused machine design questions with marked answers for exam preparation and subject revision.

machine design Mcqs
1. The crest diameter of a screw thread is same as _____________________?
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A. none of the above

B. major diameter

C. pitch diameter

D. core diameter

E. minor diameter

2. Antifriction bearings are__________________?
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A. none of the above

B. ball and roller bearings

C. sleeve bearings

D. hydrodynamic bearings

E. thin lubricated bearings

3. The permissible stress for carbon steel under static loading is generally taken as__________________?
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A. 10,000-15,000 kg/cm2

B. 2000-3000 kg/pm2

C. 3000-4000 kg/cm2

D. 4000-4500 kg/cm2

E. 7500-10,000 kg/cm2

4. If threads on a bolt are left hand, threads on nut will be_____________________?
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A. right hand with fine pitch

B. left hand with fine pitch

C. right hand with same pitch

D. left hand with same pitch

E. could be left or right hand

5. Transverse fillet welded joints are designed for________________?
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A. torsional strength

B. compressive strength

C. tensile strength

D. bending strength

E. shear strength

6. Elastic nut is a locking device in which__________________?
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A. through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at other end

B. none of the above

C. a slot is cut partly in middle of nut and then slot reduced by tightening a screw

D. hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed on the bolt causing a tight grip

E. one small nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming

7. Three different weights fall from a certain height under vacuum. They will take______________?
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A. times inversely proportional to weight to reach earth

B. same time to reach earth

C. none of the above

D. unpredictable

E. times proportional to weight to reach earth

8. In V-belt drive, belt touches______________?
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A. at bottom

B. at sides only

C. both at bottom and sides

D. could touch anywhere

E. none of the above

9. The strap end of a connecting rod of steam engine is joined by_________________?
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A. spigot socket cotter joint

B. gib of cotter joint

C. sleeve and cotter joint

D. knuckle joint

E. universal coupling

10. Silver-based solder is used for__________________?
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A. none of the above

B. flaring

C. fusion welding

D. brazing

E. soft soldering

11. The fatigue life of a part can be improved by_____________________?
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A. shot peening

B. polishing

C. heat treating

D. coating

E. electroplating

12. The deflection of a cantilever beam under load W is 8. If its width is halved, then the deflection under load W will be________________?
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A. 4-Aug

B. 28

C. 48

D. 2-Aug

E. none of the above

13. A self locking screw has________________>
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A. coefficient of friction > tangent of load angle

B. two nuts for locking

C. coarse threads

D. hole for inserting split pin

E. fine threads

14. For steel, the ultimate strength in shear as compared to ultimate strength in tension is ___________________?
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A. 2-Jan

B. 3-Jan

C. same

D. 4-Jan

E. 2/3
15. Basic hole is one_________________?
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A. whose lower as well as upper deviations are zero

B. whose upper deviation is zero

C. none of the above

D. whose lower deviation is zero

E. does not exist

16. Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to________________?
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A. static loading

B. all of the above

C. completely reversed loading

D. dynamic loading

E. combined static and dynamic loading

17. The following type of nut is used with alien bolt____________________?
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A. slotted nut

B. castle nut

C. alien nut

D. any one of the above

E. hexagonal nut

18. The fatigue limit of a material____________________?
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A. none of the above

B. is greatly decreased by poor surface conditions

C. depends mainly on core composition

D. remains same irrespective of surface conditions

E. is dependent upon yield strength of material

19. I.S. specifies following total number of grades of tolerances__________________?
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A. 16

B. 18

C. 22

D. 14

E. 20

20. Taper on the cotter and slot is provided_________________?
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A. on both the sides

B. on one side only

C. on none of the sides

D. may be provided anywhere

E. none of the above

21. A backing ring is used inside the pipe joint when making a___________________?
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A. sleeve weld

B. socket weld

C. fillet weld

D. tube weld

E. butt weld
22. In hydrostatic bearings ____________________?
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A. the oil film is maintained by supplying oil under pressure

B. do not require external supply of lubricant

C. the Oil film pressure is generated only by the rotation of the journal

D. none of the above

E. grease is used for lubrication

23. Coaxing is the procedure of increasing__________________?
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A. metal hardness by surface treatment

B. none of the above

C. fatigue limit by overstressing the metal by successively increasing loadings

D. metal resistance to corrosion by coating

E. metal strength by cycling

24. Shear stress theory is applicable for____________________?
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A. brittle materials

B. none of the above

C. elastic materials

D. all of the above

E. ductile fnaterials
25. In nitrated parts, the origins of the fatigue cracks will occur at__________________?
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A. surface

B. within the core

C. could occur anywhere

D. just below the surface

E. none of the above
26. An alien bolt is___________________?
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A. self locking bolt

B. provided with hexagonal depression in head

C. provided with countersunk head

D. used in high speed components

E. same as stud

27. When a nut is tightened by plaping a washer below it, the bolt will be subjected to following type of loads___________________?
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A. combined loads

B. compression

C. all of the above

D. tension

E. shear

28. The ratio of endurance limit in shear to the endurance limit in flexure is__________________________?
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A. 0.5

B. 0.6

C. 0.55

D. 0.4

E. 0.33

29. Which of the following is not correct procedure to increase the fatigue limit_______________?
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A. cold working

B. under-stressing

C. shot peening

D. surface decarburisation

E. all of the above

30. A stud________________________?
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A. has a head on one end and a nut fitted to the other

B. has head at one end and other end fits into a tapped hole in the other part to be joined

C. has both the ends threaded

D. has pointed threads

E. requires locking nuts

31. A tap bolt_____________________?
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A. has a head on one end and a nut fitted to the other

B. has head at one end and other end fits into a tapped hole in the other part o be joined

C. has both the ends threaded

D. has pointed threads

E. requires locking devices

32. The resultant axial load on a bolt depends on_______________?
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A. A, B. and C. above

B. relative elastic yielding (springness) of the bolt and the connected member

C. A. and B. above

D. initial tension

E. external load applied

33. Stress concentration is caused due to_____________________?
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A. abrupt change of section

B. none of the above

C. pitting atpoints or areas at which loads on a member are applied

D. all of the above

E. variation in properties of material from point to point in a member

34. The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of____________?
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A. 0.55

B. 0.45

C. 0.75

D. 0.65

E. 0.25

35. If p = bearing pressure on projected bearing area, z = absolute viscosity of lubricant, and N = speed of journal, then the bearing characteristic number is given by________________?
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A. ZN/p

B. Z/pN

C. p/ZN

D. Zp/N

E. N/Zp

36. Taper usually provided on cotter is_________________?
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A. 1 in 40

B. 1 in 5

C. 1 in 10

D. 1 in 24

E. 1 in 50

37. If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited ________________?
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A. buttress

B. square

C. metric

D. acme

E. BSW

38. Whether any core is required in wire ropes________________?
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A. no

B. very often

C. sometimes

D. yes

E. rarely

39. Stress concentration in static loading is more serious in__________________?
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A. ductile materials

B. brittle materials

C. equally serious in both cases

D. depends on other factors

E. unpredictable

40. If a spring is cut down into two springs, the stiffness of cut springs will be _________________?
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A. unpredictable

B. none of the above

C. half

D. double

E. same

41. Which process will increase the fatigue duration of parts ?
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A. decarburisation

B. electroplating

C. shot-peening

D. all of the above.

E. finishing and polishing

42. The pitch of threads on a Jock nut in comparison to pitch of nut is_________________?
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A. very fine

B. same

C. very coarse

D. coarser

E. finer

43. If an unsupported uniform cross sectional elastic bar is subjected to a longitudinal impact from a rigid bob moving with velocity v, then a compressive wave of intensity sc is propagated through the bar as follows______________________?
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A. none of the above, where E = modulus of elasticity and p = mass density

B. vVvF

C. WpE/2

D. vpE

E. IvHpE

44. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test_________________?
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A. Vicker

B. Shores sceleroscope

C. Rockwell

D. Brinell

E. none of the above

45. Eye bolts are used for_________________?
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A. transmission of power

B. absorbing shock and vibrations

C. foundation purposes

D. locking devices *

E. lifting and transportation of machines and cubicles
46. Stress concentration in cyclic loading is more serious in__________________?
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A. ductile materials

B. brittle materials

C. equally serious in both cases

D. depends on other factors

E. unpredictable

47. The draw of cotter need not exceed_________________?
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A. 25 mm

B. 10 mm

C. 20 mm

D. 5 mm

E. 3 mm
48. The connecting rod bolts are tightened up with initial tension greater than the external load so that___________________?
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A. bolts are weakest elements

B. bolts will not loosen during service

C. joint may not open up

D. the resultant load on the bolt would not be affected by the external cyclic load

E. none of the above

49. In cross or regular lay ropes_________________?
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A. wires are not twisted

B. wires in two adjacent strands are twisted in opposite direction

C. direction of twist of wires and strands are same

D. direction of twist of wires in strands is opposite to the direction of twist of strands

E. none of the above

50. Cold working________________?
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A. decreases the fatigue strength

B. increases the fatigue strength

C. none of the above

D. alone has no influence on fatigue strength

E. has no influence on fatigue strength