Machine Design 1000+ MCQ with answer for RBI Grade B officer

1. In designing a connecting rod, it is considered like __________ for buckling about X-axis.
A. Both ends hinged
B. Both ends fixed
C. One end fixed and the other end hinged
D. One end fixed and the other end free
Answer : A

2. Idler pulley is used for
A. Increasing velocity ratio
B. For applying tension
C. Changing the direction of motion of belt
D. All of these
Answer : B

3. When spring index increases, the value of Wahl's stress factor
A. Increases linearly
B. Decreases linearly
C. Remains same
D. Increases exponentially
Answer : D

4. For tight leakage joints, following type of thread is best suited
A. Metric
B. Buttress
C. Square
D. NPT (national pipe threads)
Answer : D

5. Which of the following screw thread is used for power transmission in one direction only?
A. Square threads
B. Multiple threads
C. Acme threads
D. Buttress threads
Answer : D

6. When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
A. Axially upwards
B. Axially downwards
C. Axially upwards or downwards
D. None of these
Answer : C

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

8. 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

9. The static tooth load should be __________ the dynamic load.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : C

10. 18/8 steel contains
A. 18% nickel and 8% chromium
B. 18% chromium and 8% nickel
C. 18% nickel and 8% vanadium
D. 18% vanadium and 8% nickel
Answer : B

11. Rivets are generally specified by
A. Thickness of plates to be riveted
B. Length of rivet
C. Diameter of head
D. Nominal diameter
Answer : D

12. Rankine Gordon formula for buckling is valid for
A. Long column
B. Short column
C. Short and long column
D. Very long column
Answer : C

13. The condition for maximum power transmission is that the maximum tension in the flat belt should be equal to
A. 3 Pc
B. Pc
C. Pc/3
D. 2 Pc Where, Pc = tension in belt due to centrifugal force
Answer : A

14. Which of the following statement is wrong?
A. The pitch of rivets is obtained by equating the tearing resistance of the plate to the shearing resistance of the rivets
B. The pitch of rivets should not be less than 2d, where d is the diameter of rivet hole
C. The maximum value of the pitch of rivets for a longitudinal joint of a boiler, as per I.B.R., is given by Pmax = C.t + 41.28 mm
D. According to I.B.R., the thickness of butt strap shall not be less than 5 mm
Answer : D

15. The resilience of a bolt may be increased by
A. Increasing its shank diameter
B. Increasing its length
C. Decreasing its shank diameter
D. Decreasing its length
Answer : B

16. The product of the diametral pitch and circular pitch is equal to
A. 1
B. 1/?
C. ?
D. ? × number of teeth
Answer : C

17. Basic shaft is one
A. Whose upper deviation is zero
B. Whose lower deviation is zero
C. Whose lower as well as upper deviations are zero
D. Does not exist
Answer : A

18. Plastic flow in ductile materials
A. Increases the seriousness of static loading stress concentration
B. Lessens the seriousness of static loading stress concentration
C. Has no effect on it
D. Depends on other considerations
Answer : B

19. Two rigid plates are clamped by means of bolt and nut with an initial force F. After tightening, a separating force P (P < F) is applied to the lower plate, which in turn acts on the nut. The tension in the both after this is
A. F + P
B. F P
C. P
D. F
Answer : A

20. 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

21. Eye bolts are used for
A. Foundation purposes
B. Absorbing shock and vibrations
C. Transmission of power
D. Lifting and transportation of machines and cubicles
Answer : D

22. Stress concentration in static loading is more serious in
A. Ductile materials
B. Brittle materials
C. Equally serious in both cases
D. Depends on other factors
Answer : B

23. Residual stress in materials
A. Acts when external load is applied
B. Becomes zero when external load is removed
C. Is independent of external loads
D. Is always harmful
Answer : C

24. The metal suitable for bearings subjected to heavy loads is
A. White metal
B. Silicon bronze
C. Monel metal
D. Phosphor bronze
Answer : A

25. Fibrous fracture occurs in
A. Ductile material
B. Brittle material
C. Elastic material
D. Hard material
Answer : A

26. The maximum efficiency of a square threaded screw is
A. (1 - sin?)/ (1 + sin?)
B. (1 + sin?)/ (1 - sin?)
C. (1 - sin?)/ (1 + cos?)
D. (1 + cos?)/ (1 - sin?)
Answer : A

27. The creep in the belt is due to
A. Effect of temperature on belt
B. Material of belt
C. Unequal extensions in the belt due to tight and slack side tensions
D. Stresses beyond elastic limit of belt material
Answer : C

28. 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

29. A crankshaft is a __________ shaft.
A. Transmission
B. Machine
C. Machine frame
D. None of these
Answer : B

30. In standard taper roller bearings, the angle of taper of outer raceway is
A. 5°
B. 8°
C. 15°
D. 25°
Answer : D

31. In oilness 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 required to be applied after some intervals
Answer : C

32. Tearing resistance required to tear off the plate per pitch length is (where p = Pitch of rivets, d = Dia. of rivet hole, and ?t = Permissible tensile stress for plate material)
A. p.d.?_t
B. p.t.?_t
C. (p - d) ?_t
D. (p - d) t.?_t
Answer : D

33. 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

34. Taper usually provided on cotter is
A. 1 in 5
B. 1 in 10
C. 1 in 24
D. 1 in 40
Answer : C

35. 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

36. The included angle in unified of American National threads is
A. 60°
B. 55°
C. 47°
D. 29°
Answer : A

37. In the case of an elastic bar fixed at upper end and loaded by a falling weight at lower end, the shock load produced can be decreased by
A. Decreasing the cross-section area of bar
B. Increasing the cross-section area of bar
C. Remain unaffected with cross-section area
D. Would depend upon other factors
Answer : A

38. A column is known as a long column if the slenderness ratio is
A. 40
B. 50
C. 70
D. 100
Answer : D

39. The function of a washer is to
A. Provide cushioning effect
B. Provide bearing area
C. Absorb shocks and vibrations
D. Provide smooth surface in place of rough surface
Answer : B

40. The size of a cam depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Pitch curve
Answer : A

41. 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

42. A stud
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
Answer : C

43. Cold working
A. Increases the fatigue strength
B. Decreases the fatigue strength
C. Has no influence on fatigue strength
D. Alone has no influence on fatigue strength
Answer : A

44. In a transverse fillet welded joint, the size of weld is __________ the throat of weld.
A. 0.5 times
B. Equal to
C. 2 times
D. Double
Answer : C

45. Surface endurance limit of gear material is dependent upon its
A. Elastic strength
B. Yield strength
C. Brinell hardness number
D. Toughness
Answer : C

46. The stress induced in the belt is,
A. Tensile stress
B. Compressive stress
C. Direct shear stress
D. Torsional shear stress
Answer : A

47. When a belt drive is transmitting maximum power,
A. Effective tension is equal to centrifugal tension
B. Effective tension is half of centrifugal tension
C. Driving tension on slack side is equal to centrifugal tension
D. Driving tension on tight side is twice the centrifugal tension
Answer : D

48. The shear stress at a point in a shaft subjected to a torque is
A. Directly proportional to the polar moment of inertia and to the distance of the point from the axis
B. Directly proportional to the applied torque and inversely proportional to the polar moment of inertia
C. Directly proportional to the applied torque and the polar moment of inertia
D. Inversely proportional to the applied torque and the polar moment of inertia
Answer : B

49. In order to determine the stresses in a thin cylinder due to an internal pressure, it is assumed that
A. The effect of curvature of the cylinder wall is neglected
B. The tensile stresses are uniformly distributed over the section of the walls
C. The effect of the restraining action of the heads at the end of the pressure vessel is neglected
D. All of the above
Answer : D

50. The design of shafts made of brittle materials is based on
A. Guest's theory
B. Rankine's theory
C. St Venant's theory
D. Von Mises theory
Answer : B