1000+ Machine Design Multiple Choice Question Answer [Solved]

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

2. A leaf spring in automobiles is used
A. To apply forces
B. To measure forces
C. To absorb shocks
D. To store strain energy
Answer : C

3. Which of the following screw thread is adopted for power transmission in either direction?
A. Acme threads
B. Square threads
C. Buttress threads
D. Multiple threads
Answer : B

4. The piston rod of a steam engine is usually connected to the crosshead by means of
A. Bolted joint
B. Knuckle joint
C. Cotter joint
D. Universal joint
Answer : C

5. Which of the following formula is used in designing a connecting rod?
A. Euler's formula
B. Rankine's formula
C. Johnson's straight line formula
D. Johnson's parabolic formula
Answer : B

6. The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is
A. 0.01 micron
B. 0.1 micron
C. 1 micron
D. 10 microns
Answer : C

7. During hot working of metals,
A. Porosity of the metal is largely eliminated
B. Grain structure of the metal is refined
C. Mechanical properties are improved due of refinement of grains
D. All of the above
Answer : D

8. Deep groove ball bearings are used for
A. Heavy thrust load only
B. Small angular displacement of shafts
C. Radial load at high speed
D. Combined thrust and radial loads at high speed
Answer : D

9. 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

10. In replacing the V-belts, a complete set of new belts is used instead of replacing a single damaged belt because
A. Belts are available in sets
B. Only one belt cannot be fitted with other used belts
C. The new belt will carry more than its share and result in short life
D. New and old belts will cause vibrations
Answer : C

11. The radial distance of a tooth from the pitch circle to the top of the tooth is called
A. Addendum
B. Dedendum
C. Clearance
D. Working depth
Answer : A

12. The stretching in a belt can be controlled by __________ the stress in the belt.
A. Reducing
B. Increasing
C. Both A and B
D. None of these
Answer : A

13. 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

14. The temperature required for full annealing in hypereutectoid steel is
A. 50°C above upper critical temperature
B. 50°C below upper critical temperature
C. 50°C above lower critical temperature
D. 50°C below lower critical temperature
Answer : A

15. 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

16. The distribution of the forces along the length of key fitted in a shaft
A. Varies linearly
B. Is uniform throughout
C. Varies exponentially, being more near the torque-input end
D. Varies exponentially, being less near the torque-input end
Answer : C

17. In a full journal bearing, the angle of contact of the bearing with the journal is
A. 120°
B. 180°
C. 270°
D. 360°
Answer : D

18. When the belt is transmitting maximum power,
A. The tension in tight side is twice the centrifugal tension
B. The tension in slack side is equal to the centrifugal tension
C. The tension in tight side is thrice the centrifugal tension
D. None of the above
Answer : A

19. Which of the following statement is correct?
A. The cold rolled shafting is stronger than hot rolled shafting
B. The hot rolled shafting is stronger than cold rolled shafting
C. The cold rolled and hot rolled shaftings are equally strong
D. The shafts are not made by rolling process
Answer : A

20. 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

21. When two springs are in series (having stiffness K), the equivalent stiffness will be
A. K
B. K/2
C. 2K
D. K/4
Answer : B

22. Two helical springs of the same material and of equal circular crosssection, length and number of turns, but having radii 80 mm and 40 mm, kept concentrically (smaler radius spring within the larger radius spring), are compressed between two parallel planes with a load W. The inner spring will carry a load equal to
A. W/2
B. 2W/3
C. W/9
D. 8W/9
Answer : B

23. 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

24. The power transmitted by belt drive depends upon
A. Belt velocity
B. Initial belt tension
C. Arc of contact
D. All of the above
Answer : D

25. 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

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

27. Auto frettage is the method of
A. Joining thick cylinders
B. Calculating stresses in thick cylinders
C. Pre-stressing thick cylinders
D. Increasing the life of thick cylinders
Answer : C

28. The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (D) is given by (where T = Number of teeth on the sprocket)
A. p = D sin (90°/T)
B. p = D sin (120°/T)
C. p = D sin (180°/T)
D. p = D sin (360°/T)
Answer : C

29. Which is positive drive?
A. Flat belt drive
B. V-belt drive
C. Crossed belt drive
D. Timing belt
Answer : D

30. The application of third type levers is found in
A. A pair of tongs
B. Hand wheel of a punching press
C. Lever of a loaded safety valve
D. Handle of a hand pump
Answer : A

31. Stress concentration factor is defined as the ratio of
A. Maximum stress to the endurance limit
B. Nominal stress to the endurance limit
C. Maximum stress to the nominal stress
D. Nominal stress to the maximum stress
Answer : C

32. A metal pipe of 1 m diameter contains a fluid having a pressure of 1 N/mm². If the permissible tensile stress in the metal is 20 N/mm², then the thickness of the metal required for making the pipe will be
A. 5 mm
B. 10 mm
C. 15 mm
D. 25 mm
Answer : D

33. According to Indian standard specifications, 100 H6/g5 means that
A. Tolerance grade for the hole is 6 and for the shaft is 5
B. Tolerance grade for the shaft is 6 and for the hole is 5
C. Tolerance grade for the shaft is 4 to 8 and for the hole is 3 to 7
D. Tolerance grade for the hole is 4 to 8 and for the shaft is 3 to 7
Answer : A

34. 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

35. The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that
A. It is subjected to a higher cyclic loading than the outer side
B. It is subjected to a higher stress than the outer side
C. It is more stretched than the outer side during the manufacturing process
D. It has a lower curvature than the outer side
Answer : A

36. For unequal width of butt straps, the thicknesses of butt straps are
A. 0.75 t for narrow strap on the inside and 0.625 t for wide strap on the outside
B. 0.75 t for wide strap on the inside and 0.625 t for narrow strap on the outside
C. 0.75 t for both the straps on the inside and outside
D. 0.625 t for both the straps on the inside and outside
Answer : B

37. According to Indian standards, a bolt thread of 6 mm size of coarse pitch and with allowance on the threads and normal tolerance grade is designated as
A. M6
B. M8
C. M6 - 8d
D. M8 - 6d
Answer : C

38. The endurance limit of a material with finished surface in comparison to rough surface is
A. More
B. Less
C. Same
D. More or less depending on quantum of load
Answer : A

39. 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

40. 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

41. The crest diameter of a screw thread is same as
A. Major diameter
B. Minor diameter
C. Pitch diameter
D. Core diameter
Answer : A

42. 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

43. 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

44. Set screws are
A. Similar to small size tap bolts except that a greater variety of shapes of heads are available
B. Slotted for a screw driver and generally used with a nut
C. Used to prevent relative motion between parts
D. Similar to stud
Answer : C

45. 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

46. The resultant axial load on a bolt depends on
A. Initial tension
B. External load applied
C. Relative elastic yielding (springness) of the bolt and the connected member
D. All of the above
Answer : D

47. 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

48. In the assembly of pulley, key and shaft
A. Pulley is made the weakest
B. Key is made the weakest
C. Key is made the strongest
D. All the three are designed for equal strength
Answer : B

49. 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

50. The designation M 33 × 2 of a bolt means
A. Metric threads of 33 numbers in 2 cm
B. Metric threads with cross-section of 33 mm
C. Metric threads of 33 mm outside diameter and 2 mm pitch
D. Bolt of 33 mm nominal diameter having 2 threads per cm
Answer : C