Machine Design 1000+ MCQ with answer for SBI Clerk

1. In the levers of first type, the mechanical advantage is __________ one.
A. Less than
B. Equal to
C. More than
D. None of these
Answer : C

2. In case of thick cylinders, the tangential stress across the thickness of cylinder is
A. Maximum at the outer surface and minimum at the inner surface
B. Maximum at the inner surface and minimum at the outer surface
C. Maximum at the inner surface and zero at the outer surface
D. Maximum at the outer surface and zero at the inner surface
Answer : B

3. A tube has the following advantage over pipe
A. Lighter and easier to handle
B. Greater shock absorption
C. Smoother inside walls
D. All of the above
Answer : D

4. A spring of stiffness 1000 N/m is stretched initially by 100 mm from the undeformed position. The work required to stretch it by another 100 mm is
A. 5 N-m
B. 7 N-m
C. 10 N-m
D. 15 N-m
Answer : D

5. For applications involving high stresses in one direction only the following type of thread would be best suited
A. ISO metric thread
B. Acme thread
C. Square thread
D. Buttress thread
Answer : D

6. Stress concentration is caused due to
A. Variations in load acting on a member
B. Variations in properties of materials in a member
C. Abrupt change of cross-section
D. All of these
Answer : C

7. In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as
A. Helix angle
B. Pressure angle
C. Pitch lead angle
D. None of these
Answer : A

8. Creep in belt is due to
A. Material of the belt
B. Material of the pulley
C. Uneven extensions and contractions due to varying tension
D. All of the above
Answer : C

9. For steel, the ultimate strength in shear as compared to ultimate strength in tension is
A. 1/2
B. 1/3
C. 1/4
D. 2/3
Answer : D

10. In a flange coupling, the flanges are coupled together by means of
A. Bolts and nuts
B. Studs
C. Headless taper bolts
D. None of these
Answer : A

11. The objective of caulking in a riveted joint is to make the joint
A. Free from corrosion
B. Stronger in tension
C. Free from stress
D. Leak-proof
Answer : D

12. Brittle coating technique is used for
A. Determining brittleness
B. Protecting metal against corrosion
C. Protecting metal against wear and tear
D. Experimental stress analysis
Answer : D

13. A compound cylinder with inner radius 50 mm and outer radius 70 mm is made by shrinking one cylinder on to the other cylinder, the junction radius is 60 mm and the junction pressure is 1.1 N/mm². The maximum hoop stress developed in the inner cylinder is
A. 3.6 N/mm² compression
B. 3.6 N/mm² tension
C. 7.2 N/mm² compression
D. 7.2 N/mm² tension
Answer : C

14. Which of the following statement is correct regarding power screws?
A. The efficiency of a self locking screw can not be more than 50%
B. The efficiency of Acme (trapezoidal) thread is less than that of a square thread
C. If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%
D. (A) and (B) Only
Answer : D

15. In a gear, having Involute teeth, the normal to the Involute is a tangent to the
A. Base circle
B. Pitch circle
C. Addendum circle
D. Dedendum circle
Answer : A

16. A bench vice has following type of threads
A. Metric
B. Square
C. Buttress
D. Acme
Answer : D

17. A localised compressive stress at the area of contact between two members is known as
A. Tensile stress
B. Bending stress
C. Bearing stress
D. Shear stress
Answer : C

18. The angle of twist of shaft is
A. Directly proportional to (shaft diameter)²
B. Inversely proportional to (shaft diameter)²
C. Directly proportional to (shaft diameter)?
D. Inversely proportional to (shaft diameter)?
Answer : D

19. If threads on a bolt are left hand, threads on nut will be
A. Right hand with same pitch
B. Left hand with same pitch
C. Could be left or right hand
D. Right hand with fine pitch
Answer : B

20. The connecting rod bolts are tightened up with initial tension greater than the external load so that
A. Joint may not open up
B. Bolts are weakest elements
C. The resultant load on the bolt would not be affected by the external cyclic load
D. Bolts will not loosen during service
Answer : C

21. In most machine members, the damping capacity of the material should be
A. Low
B. Zero
C. High
D. Could be anything
Answer : C

22. The backlash for spur gears depends upon
A. Module
B. Tooth profile
C. Both module and pitch line velocity
D. Pitch line velocity
Answer : C

23. According to I.B.R., the factor of safety of riveted joint should not be less than
A. 1
B. 2
C. 3
D. 4
Answer : D

24. According to I.B.R., when the thickness of boiler shell (t) is greater than 8 mm, then the diameter of rivet hole (d) is obtained by
A. Equating tearing resistance of the plate to the shearing resistance of the rivets
B. Equating tearing resistance of the plate to the crushing resistance of the rivets
C. Equating shearing resistance to the crushing resistance of the rivets
D. None of the above
Answer : B

25. Guest's theory of failure is applicable for following type of materials
A. Brittle
B. Ductile
C. Elastic
D. Plastic
Answer : B

26. In hydrostatic bearings
A. The Oil film pressure is generated only by the rotation of the journal
B. The oil film is maintained by supplying oil under pressure
C. Do not require external supply of lubricant
D. Grease is used for lubrication
Answer : B

27. The speed of the sprocket reduces as the chain pitch __________ for a given number of teeth.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A

28. The initial tension (in newtons) in a bolt used for making a fluid tight joint like steam engine cover joints, is calculated by the relation (where d = Nominal diameter of bolt in mm)
A. 1420 d
B. 1680 d
C. 2080 d
D. 2840 d
Answer : D

29. Which of the following statement is correct for gears?
A. The pitch circle diameter is equal to the product of module and number of teeth
B. The addendum is less than dedendum
C. The pitch circle is always greater than the base circle
D. All of the above
Answer : D

30. Silver based solder is used for
A. Flaring
B. Brazing
C. Soft soldering
D. Fusion welding
Answer : B

31. A fast and loose pulley drive is used when
A. Shafts are arranged parallel and rotate in the opposite directions
B. Shafts are arranged parallel and rotate in the same directions
C. Shafts are arranged at right angles and rotate in one definite direction
D. Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
Answer : D

32. The pipe joint mostly used for pipes carrying water at low pressures is
A. Socket joint
B. Nipple joint
C. Union joint
D. Spigot and socket joint
Answer : A

33. The ratio of driving tensions for flat belts, neglecting centrifugal tension, is (where T?, and T? = Tensions on the tight and slack sides of belt respectively, ? = Coefficient of friction, between the belt and pulley, and ? = Angle of contact)
A. T?/T? = ??
B. log (T?/T?) = ??
C. T?/T? =e??
D. T?/T? = log ??
Answer : C

34. The difference between the tooth space and the tooth thickness as measured on the pitch circle, is called
A. Working depth
B. Clearance
C. Backlash
D. Face width
Answer : C

35. Jam nut is a locking device in which
A. One smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
B. A slot is cut partly in middle of nut and then slot reduced by tightening a screw
C. A hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip
D. Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end
Answer : A

36. The ratio of circumferential stress to longitudinal stress in a thin cylinder subjected to an internal pressure is
A. ½
B. 1
C. 2
D. 4
Answer : C

37. A bolt of M 24 × 2 means that
A. The pitch of the thread is 24 mm and depth is 2 mm
B. Cross-sectional area of the threads is 24 mm²
C. The nominal diameter of bolt is 24 mm and pitch is 2 mm
D. The effective diameter of bolt is 24 mm and there are 2 threads per cm
Answer : C

38. In worm gears, the pressure angle is ________ the angle between two inclined faces in axial plane.
A. Half
B. Twice
C. Thrice
D. None of these
Answer : A

39. The design calculations for members subject to fluctuating loads with the same factor of safety, yield the most conservative estimates when using
A. Gerber relation
B. Soderberg relation
C. Goodman relation
D. None of these
Answer : C

40. According to Indian standards, total numbers of tolerance grades are
A. 8
B. 12
C. 18
D. 20
Answer : C

41. A double strap butt joint (with equal straps) is
A. Always in single shear
B. Always in double shear
C. Either in single shear or double shear
D. Any one of these
Answer : B

42. In order to avoid tearing of the plate at an edge, the distance from the centre line of the rivet hole to the nearest edge of the plate should be equal to (where d = Diameter of rivet hole)
A. d
B. 1.5 d
C. 2.5 d
D. 2 d
Answer : B

43. The rolling contact bearings as compared to sliding contact bearings have
A. Low starting and low running friction except at very high speeds
B. Accuracy of shaft alignment
C. Small overall dimensions
D. All of the above
Answer : D

44. The size of a gear is usually specified by
A. Pressure angle
B. Pitch circle diameter
C. Circular pitch
D. Diametral pitch
Answer : B

45. The face of the tooth is the
A. Surface of the top of the tooth
B. Surface of the tooth above the pitch surface
C. Surface of the tooth below the pitch surface
D. Width of the tooth measured along the pitch circle
Answer : B

46. According to Indian standards, the diameter of rivet hole is made larger than the basic size of rivet by
A. 0.5 mm upto rivet diameter of 24 mm
B. 1 mm for rivet diameter from 27 mm to 36 mm
C. 2 mm for rivet diameter from 39 mm to 48 mm
D. All of the above
Answer : C

47. Which is correct statement?
A. A member made of steel will generally be more rigid than a member of equal load carrying ability made of cast iron
B. A member made of cast iron will generally be more rigid than a member of equal load carrying ability made of steel
C. Both will be equally rigid
D. Which one is rigid will depend on several other factors
Answer : B

48. Lewis equation in gears is used to find the
A. Tensile stress in bending
B. Shear stress
C. Compressive stress in bending
D. Fatigue stress
Answer : C

49. The allowable static stress for steel gears is approximately __________ of the ultimate tensile stress.
A. One-fourth
B. One-third
C. One-half
D. Double
Answer : B

50. The strength of a riveted joint is equal to
A. Tearing strength of plate (P_t)
B. Shearing strength of rivet (P_s)
C. Crushing strength of rivet (P_c)
D. Least value of P_t P_s and P_c
Answer : D