Machine Design 1000+ MCQ with answer for SSC CHSL

1. The spring mostly used in gramophones is
A. Helical spring
B. Conical spring
C. Flat spiral spring
D. Volute spring
Answer : C

2. In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set in order to
A. Reduce vibration
B. Reduce slip
C. Ensure uniform loading
D. Ensure proper alignment
Answer : C

3. 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

4. Oil in journal bearing should be applied at the point where load is
A. Nil or lightest
B. Maximum
C. Average
D. Any one of the above
Answer : A

5. A connecting rod should be
A. Strong in buckling about X-axis
B. Strong in buckling about Y-axis
C. Equally strong in buckling about X-axis and Y-axis
D. Any one of the above
Answer : C

6. When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
A. 4F/ ?d²
B. 6F/ ?d²
C. 8F/ ?d²
D. 16F/ 3?d²
Answer : D

7. Shear stress theory is applicable for
A. Ductile materials
B. Brittle materials
C. Elastic materials
D. All of the above
Answer : A

8. 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

9. According to I.B.R., the distance between the rows of rivets, for equal number of rivets in more than one row for lap joint or butt joint (chain riveting) shall not be less than
A. d
B. 1.5 d
C. 2d
D. 2.5 d
Answer : C

10. When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as
A. Angular bevel gears
B. Mitre gears
C. Internal bevel gears
D. Crown bevel gears
Answer : D

11. For circumferential joint in boilers, the type of joint used is
A. Butt joint with single cover plate
B. Butt joint with double cover plate
C. Lap joint with one ring overlapping the other
D. Any one of the above
Answer : C

12. Machine 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 two parts
D. Similar to stud
Answer : B

13. Rankine's theory is used for
A. Brittle materials
B. Ductile materials
C. Elastic materials
D. Plastic materials
Answer : A

14. 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

15. A flange coupling is used to connect two shafts
A. Which are perfectly aligned
B. Which are not in exact alignment
C. Have lateral misalignment
D. Whose axes intersect at a small angle
Answer : A

16. 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

17. The value of Lewis form factor used in design of gears is
A. Dependent on number of teeth of a gear
B. Dependent on system of teeth
C. Independent of size of teeth
D. All of these
Answer : D

18. The suitable material for belt used in flour mill is
A. Leather
B. Rubber
C. Canvas or cotton duck
D. Balata gum
Answer : C

19. When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
A. 2WD³n/Gd?
B. 4WD³n/Gd?
C. 8WD³n/Gd?
D. 16WD³n/Gd?
Answer : C

20. If the size of a standard specimen for a fatigue testing machine is increased, the endurance limit for the material will
A. Have same value as that of standard specimen
B. Increase
C. Decrease
D. None of these
Answer : C

21. The dedendum circle diameter is equal to (where ? = Pressure angle)
A. Pitch circle diameter × cos?
B. Addendum circle diameter × cos?
C. Clearance circle diameter × cos?
D. Pitch circle diameter × sin?
Answer : A

22. In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where ? = Coefficient of friction between the blocks and the drum, ? = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)
A. T?/T? = ?? × n
B. T?/T? = (??)ⁿ
C. T?/T? = [(1 - ? tan?)/ (1 + ? tan?)]ⁿ
D. T?/T? = [(1 + ? tan?)/ (1 - ? tan?)]ⁿ
Answer : D

23. A single strap butt joint is always in __________ shear.
A. Single
B. Double
C. Triple share
D. None of these
Answer : A

24. According to I.B.R., shearing resistance required to shear off the rivet per pitch length (in double shear) is (where n = Number of rivets per pitch length)
A. (?/4) d² × ? × n
B. 1.875 × (?/4) d² × ? × n
C. 2 × (?/4) d² × ? × n
D. 3 × (?/4) d² × ? × n
Answer : B

25. Tapered roller bearings can take
A. Axial load only
B. Both radial and axial loads and the ratio of these being greater than unity
C. Radial load only
D. Both radial and axial loads and the ratio of these being less than unity
Answer : B

26. 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

27. If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation
A. 124 d
B. 138 d
C. 151 d
D. 168 d
Answer : D

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

29. A steel containing upto 0.15% carbon is known as
A. Mild steel
B. Dead mild steel
C. Medium carbon steel
D. High carbon steel
Answer : B

30. Soderberg relation is based on __________ of the material whereas all other failure relation for dynamic loading are based on ultimate strength of the material.
A. Elastic strength
B. Yield strength
C. Shear strength
D. None of these
Answer : B

31. The dedendum is the radial distance from the
A. Pitch circle to the top of a tooth
B. Pitch circle to the bottom of a tooth
C. Top of a tooth to the bottom of a tooth
D. Addendum circle to the clearance circle
Answer : B

32. The draw of cotter need not exceed
A. 3 mm
B. 5 mm
C. 10 mm
D. 20 mm
Answer : A

33. For standard coarse threads of nut, the threads will be as strong in failure by shear as the bolt in tension, if the height of nut (h) is approximately
A. 0.4 times
B. 0.6 times
C. 0.7 times
D. 0.8 times
Answer : A

34. The material used for brake lining should have __________ coefficient of friction.
A. Low
B. High
C. Moderate
D. None of these
Answer : B

35. In designing a flange coupling, the pitch circle diameter of bolts is taken as (where d = Diameter of the shaft)
A. 2d
B. 3d
C. 4d
D. 5d
Answer : B

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. A backing ring is used inside the pipe joint when making a
A. Butt weld
B. Fillet weld
C. Sleeve weld
D. Socket weld
Answer : A

38. 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

39. 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

40. Spring stiffness is
A. Ratio of coil diameter to wire diameter
B. Load required to produce unit deflection
C. Its capability of storing energy
D. Its ability to absorb shocks
Answer : B

41. The function of cutting oil when threading a pipe is to
A. Provide cooling action
B. Lubricate the dies
C. Help removes chips
D. All of the above
Answer : D

42. Allen bolts are
A. Self locking bolts
B. Designed for shock load
C. Used in aircraft application
D. Provided with hexagonal depression in head
Answer : D

43. The shock absorbing capacity of a bolt may be increased by
A. Increasing its shank diameter
B. Decreasing its shank diameter
C. Tightening the bolt properly
D. Making the shank diameter equal to core diameter of thread
Answer : B

44. The maximum bending stress in a curved beam having symmetrical section always occur at the
A. Centroidal axis
B. Neutral axis
C. Inside fibre
D. Outside fibre
Answer : C

45. A column of length l is fixed at both ends. The equivalent length of the column is
A. l/2
B. l/?2
C. l
D. 2 l
Answer : A

46. In cylindrical cams, the follower moves
A. In a direction perpendicular to the cam axis
B. In a direction parallel to the cam axis
C. In any direction irrespective of cam axis
D. Along the cam axis
Answer : B

47. In leaf springs, the longest leaf is known as
A. Master leaf
B. Lower leaf
C. Upper leaf
D. None of these
Answer : A

48. The velocity factor for precision metallic gears cut with high accuracy and operating at velocities upto 20 m/s is equal to
A. 0.75/ (0.75 + ?v)
B. 3/ (3 + v)
C. 4.5/ (4.5 + v)
D. 6/ (6 + v)
Answer : A

49. In a hydrodynamic lubricated bearing
A. There is a thick film of lubricant between the journal and the bearing
B. There is a thin film of lubricant between the journal and the bearing
C. The lubricant is forced between the journal and the bearing, by external pressure
D. There is no lubricant between the journal and the bearing
Answer : A

50. The ball bearings are, usually, made from
A. Low carbon steel
B. High carbon steel
C. Medium carbon steel
D. High speed steel
Answer : C