Machine Design Multiple Choice Questions Pdf
1. The ratio of belt tensions (p1/p2) considering centrifugal force in flat belt is given by
Where m = mass of belt per meter (kg/m)
v = belt velocity (m/s)
f = coefficient of friction
a = angle of wrap (radians)
A. (P1 – mv²)/ (P2 – mv²) = eᶠα
B. P1 / P2 = eᶠα
C. P1 / P2 = e–ᶠα
D. (P1 – mv²)/ (P2 – mv²) = e–ᶠα
Answer: A
2. The ultimate strength of steel in tension in comparison to shear is in the ratio of
A. 1: 1
B. 2:1
C. 3: 2
D. 2: 3
Answer: C
3. In radial cams, the follower moves
A. In a direction parallel to the cam axis
B. In a direction perpendicular to the cam axis
C. In any direction irrespective of cam axis
D. Along the cam axis
Answer: B
4. The permissible stress for carbon steel under static loading is generally taken as
A. 2000-3000 kg/m²
B. 3000-4000 kg/cm²
C. 4000-4500 kg/cm²
D. 7500-10,000 kg/cm²
Answer: C
5. The property of a material which enables it to resist fracture due to high impact loads is known as
A. Elasticity
B. Endurance
C. Strength
D. Toughness
Answer: D
6. 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
7. A hot short metal is
A. Brittle when cold
B. Brittle when hot
C. Brittle under all conditions
D. Ductile at high temperature
Answer: B
8. In case of pressure vessels having closed ends, the fluid pressure induces
A. Longitudinal stress
B. Shear stress
C. Circumferential stress
D. None of these
Answer: A
9. Guest’s theory of failure is applicable for following type of materials
A. Brittle
B. Ductile
C. Elastic
D. Plastic
Answer: B
10. A V-belt designated as B 4430 LP has
A. 4430 mm as diameter of small pulley
B. 4430 mm as nominal pitch length
C. 4430 mm as diameter of large pulley
D. 4430 mm as centre distance between pulleys
Answer: B
11. Rankine’s theory of failure is applicable for following type of materials
A. Brittle
B. Ductile
C. Elastic
D. Plastic
Answer: A
12. Screws used for power transmission should have
A. Very fine threads
B. High efficiency
C. Low efficiency
D. Strong teeth
Answer: B
13. The value of stress concentration factor depends upon
A. Material and geometry of the part
B. Geometry of the part
C. Material of the part
D. None of these
Answer: D
14. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test
A. Brinell
B. Rockwell
C. Vickers
D. None of the above
Answer: A
15. Resilience of a material is important, when it is subjected to
A. Combined loading
B. Fatigue
C. Thermal stresses
D. Shock loading
Answer: D
16. The sleeve or muff coupling is designed as a
A. Dun cylinder
B. Hollow shaft
C. Solid shaft
D. Thick cylinder
Answer: B
17. 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
18. If a load W is applied instantaneously on a bar; Then the stress induced in bar will
A. Be independent of ratio of mass of load W to mass of bar (y)
B. Increase with increase in y
C. Decrease with decrease in y
D. Depend on other considerations
Answer: A
19. According to Indian standard specifications, 100 H6/g5 means that the
A. Basic size is 100 mm
B. Actual size is 100 mm
C. Difference between the actual size and basic size is 100 mm
D. None of the above
Answer: A
20. The power transmitted by the belt drive can be increased by
A. Increasing the initial tension in the belt
B. Dressing the belt to increase the coefficient of friction
C. Increasing wrap angle by using idler pulley
D. All of the above methods
Answer: D
21. Surface endurance limit of gear material is dependent upon its
A. Elastic strength
B. Yield strength
C. Brinell hardness number
D. Toughness
Answer: C
22. 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. Crown bevel gears
B. Angular bevel gears
C. Mitre gears
D. Internal bevel gears
Answer: A
23. 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
24. Stress concentration is caused due to
A. Variation in properties of material from point to point in a member
B. Pitting at points or areas at which loads on a member are applied
C. Abrupt change of section
D. All of the above
Answer: D
25. 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
26. When screw threads are to be used in a situation where power is being transmitted in one direction only, then the screw threads suitable for this will be
A. Knuckle threads
B. Square threads
C. Acme threads
D. Buttress threads
Answer: D
27. Slenderness ratio is the ratio of
A. Effective length of column to least radius of gyration of the column
B. Width of column to depth of column
C. Maximum size of column to minimum size of column
D. Effective length of column to width of column
Answer: A
28. 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
29. The size of a gear is usually specified by
A. Pressure angle
B. Pitch circle diameter
C. Circular pitch
D. Diametral pitch
Answer: B
30. When the speed of belt increases,
A. The coefficient of friction between the belt and pulley decreases
B. The coefficient of friction between the belt and pulley increases
C. The power transmitted will decrease
D. The power transmitted will increase
Answer: C
31. The load cup of a screw jack is made separate from the head of the spindle to
A. Prevent the rotation of load being lifted
B. Enhance the load carrying capacity of the jack
C. Reduce the effort needed for lifting the working load
D. Reduce the value of frictional torque
Answer: A
32. The centrifugal tension in belts
A. Decreases the power transmitted
B. Increases the power transmitted
C. Increase the wrap angle
D. Increases the belt tension without increasing power transmission
Answer: D
33. Stress concentration in cyclic loading is more serious in
A. Ductile materials
B. Brittle materials
C. Equally serious in both cases
D. Depends on other factors
Answer: A
34. 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
A. Dynamic loading
B. Static loading
C. Combined static and dynamic loading
D. Completely reversed loading
Answer: D
35. An Involute pinion and gear are in mesh. If both have the same size of addendum, then there will be interference between the
A. Tip of the pinion and flank of gear
B. Tip of the gear and flank of pinion
C. Flanks of both gear and pinion
D. Tip of both gear and pinion
Answer: B
36. Pick up wrong statement. Fatigue strength can be increased by
A. Cold working
B. Shot peening
C. Grinding and lapping surface
D. Hot working
Answer: D
37. Which of the following is not correct procedure to increase the fatigue limit?
A. Cold working
B. Shot peening
C. Surface decarburisation
D. Under stressing
Answer: C
38. 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
39. Coaxing is the procedure of increasing
A. Metal strength by cycling
B. Metal hardness by surface treatment
C. Metal resistance to corrosion by coating
D. Fatigue limit by over-stressing the metal by successively increasing loadings
Answer: D
40. 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
41. The belt slip occurs due to
A. Heavy load
B. Loose belt
C. Driving pulley too small
D. Any one of the above
Answer: D
42. Which is correct statement? Stress concentration in static loading is
A. Very serious in brittle materials and less serious in ductile materials
B. Very serious in ductile materials and less serious in brittle materials
C. Equally serious in both types of materials
D. Seriousness would depend on other factors
Answer: A
43. 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
44. The notch angle of the Izod impact test specimen is
A. 10°
B. 20°
C. 30°
D. 45°
Answer: D
45. In Vickers hardness testing, the pyramid indentor apex is
A. 40°
B. 122°
C. 136°
D. 152°
Answer: C
46. The toughness of a material _________ when it is heated
A. Does not change
B. Increases
C. Decreases
D. None of the Above
Answer: C
47. The number of slots in a 25 mm castle nut is
A. 8
B. 6
C. 4
D. 2
Answer: A
48. 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
49. The rolling contact bearings are known as
A. Thick lubricated bearings
B. Plastic bearings
C. Antifriction bearings
D. Thin lubricated bearings
Answer: C
50. 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
51. Yield point in fatigue loading as compared to static loading is
A. Same
B. Higher
C. Lower
D. Depends on other factors
Answer: C
52. The arms of the pulleys for flat belt drive have
A. Elliptical cross-section
B. Major axis in plane of rotation
C. Major axis twice the minor axis
D. All the three characteristics
Answer: D
53. 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
54. In a marine flange coupling, the thickness of flange is taken as
A. d/2
B. d/3
C. 3d/4
D. d/4
Answer: B
55. The building up of worn and undersized parts, subjected to repeated loads by electroplating is
A. Best method
B. Extremely hazardous
C. Has no effect as regards fatigue strength
D. Cheapest method
Answer: A
56. In nitrated parts, the origins of the fatigue cracks will occur at
A. Surface
B. Just below the surface
C. Within the core
D. None of the above
Answer: D
57. The objective of idler pulley in belt drive is to
A. Decrease the tendency of belt to slip
B. Increase the power transmission capacity
C. Increase the wrap angle and belt tension
D. All the above objectives
Answer: D
58. The constant factor in case of R10 series of preferred numbers is
A. 1.06
B. 1.12
C. 1.26
D. 1.58
Answer: C
59. Which one of the following is a positive drive?
A. V-belt drive
B. Rope drive
C. Crossed flat belt drive
D. Chain drive
Answer: D
60. Which process will increase the fatigue duration of parts?
A. Finishing and polishing
B. Shot-peening
C. De-carburisation
D. Electroplating
61. In most machine members, the damping capacity of the material should be
A. Low
B. Zero
C. High
D. Could be anything
Answer: C
62. 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
63. The ratio of endurance limit in shear to the endurance limit in flexure is
A. 0.33
B. 0.4
C. 0.5
D. 0.55
Answer: D
64. 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
65. A transmission shaft includes
A. Over head shaft
B. Counter shaft
C. Line shaft
D. All of these
Answer: D
66. The groove angle of pulleys for V-belt is
A. 340 to 360
B. 420 to 450
C. More than 400
D. 300 to 320
Answer: A
67. In unilateral system of tolerance, the tolerance is allowed on
A. Both sides of the actual size
B. One side of the actual size
C. One side of the nominal size
D. Both sides of the nominal size
Answer: C
68. 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
69. 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
70. The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of
A. 0.45
B. 0.55
C. 0.65
D. 0.75
Answer: D
71. A locking device in which the bottom cylindrical portion is recessed to receive the tip of the locking set screw, is called
A. Ring nut
B. Castle nut
C. Sawn nut
D. Jam nut
Answer: A
72. A taper key which fits half in the key way of the hub and half in the key way of shaft, is known as
A. Angular bevel gears
B. Mitre gears
C. Crown Bevel gears
D. Internal bevel gears
Answer: B
73. At low temperatures (say 75°C) the notched bar impact value of steel
A. Increases markedly
B. Decreases markedly
C. Remain same
D. Depends on heat treatment carried out
Answer: B
74. The taper on cotter varies from
A. 1 in 24 to 1 in 20
B. 1 in 15 to 1 in 10
C. 1 in 32 to 1 in 24
D. 1 in 48 to 1 in 24
Answer: D
75. A bolt
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. Is provided with pointed threads
Answer: A
76. If P1 and P2 are the tight and slack side tensions in the belt, then the initial tension Pi (according to Barth) will be equal to (Where, Pc is centrifugal tension)
A. [(√P1 + √P2)/2]²
B. P1 + P2
C. ⅟2 × (P1 + P2)
D. [⅟2 × (P1 + P2)] + Pc
Answer: A
77. 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
78. Shear stress theory is applicable for
A. Ductile materials
B. Brittle materials
C. Elastic materials
D. All of the above
Answer: A
79. When the shaft rotates in anticlockwise direction at slow speed in a bearing, it will
A. Have contact at the bottom most of the bearing
B. Move towards right of the bearing making no metal to metal contact
C. Move towards right of the bearing making the metal to metal contact
D. Move towards left of the bearing making metal to metal contact
Answer: D
80. A tap bolt
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: B
81. 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
82. In a horizontal flat belt drive, it is customary to use
A. Bottom side of belt as slack side
B. Top side of belt as slack side
C. Idler pulley
D. None of the above
Answer: B
83. The included angle in unified of American National threads is
A. 60°
B. 55°
C. 47°
D. 29°
Answer: A
84. For a shaft diameter of 200 mm, the number of bolts in a marine flange coupling should be
A. 8
B. 6
C. 4
D. 10
Answer: A
85. 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
86. Cap 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. Provided with detachable caps
Answer: A
87. If P1 and P2 are the tight and slack side tensions in the belt, then the initial tension Pi (neglecting centrifugal tension) will be equal to (Where, Pc is centrifugal tension)
A. P1 – P2
B. P1 + P2
C. ⅟2 × (P1 + P2)
D. [⅟2 × (P1 + P2)] + Pc
Answer: C
88. An alien bolt is
A. Self locking bolt
B. Same as stud
C. Provided with hexagonal depression in head
D. Used in high speed components
Answer: C
89. The deflection of a cantilever beam under load W is 8. If its width is halved, then the deflection under load W will be
A. 2/8
B. 8/2
C. 4/8
D. 8/4
Answer: C
90. Ball bearing type screws are found in following application
A. Screw jack
B. Aeroplane engines
C. Crane
D. Steering mechanism
Answer: D
91. 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
92. A machine part subjected to _________ is called a strut.
A. An axial compressive force
B. A tangential force
C. An axial tensile force
D. Any one of these
Answer: A
93. 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
94. The edges of a boiler plate are bevelled to an angle of
A. 30°
B. 45°
C. 60°
D. 80°
Answer: D
95. The stress induced in the belt is,
A. Tensile stress
B. Compressive stress
C. Direct shear stress
D. Torsional shear stress
Answer: A
96. Which of the following is a permanent fastening?
A. Bolts
B. Keys
C. Cotters
D. Rivets
Answer: D
97. In order to avoid tearing of the plate at edge, the distance from the center line of the rivet hole to the nearest edge of the plate in terms of dia. of rivet d should be equal to
A. d
B. 1.25 d
C. 1.5 d
D. 1.75 d
Answer: C
98. The dedendum circle diameter is equal to (where φ = Pressure angle)
A. Pitch circle diameter × cosφ
B. Addendum circle diameter × cosφ
C. Clearance circle diameter × cosφ
D. Pitch circle diameter × sinφ
Answer: A
99. If the tearing efficiency of a riveted joint is 75%, then the ratio of diameter of rivet to the pitch is equal to
A. 0.2
B. 0.25
C. 0.50
D. 0.6
Answer: B
100. Transverse fillet welded joints are designed for
A. Tensile strength
B. Compressive strength
C. Shear strength
D. Bending strength
Answer: A
101. A sliding bearing which can support steady loads without any relative motion between the journal and the bearing, is called
A. Hydrostatic lubricated bearing
B. Hydrodynamic lubricated bearing
C. Boundary lubricated bearing
D. Zero film bearing
Answer: A
102. 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
103. When the belt is transmitting maximum power, the belt speed should be
(Where, m = mass of belt per meter (kg/m) and Pmax = maximum permissible tension in belt (N))
A. √(Pmax / 2m)
B. √(Pmax / 3m)
C. √(Pmax / m)
D. √(3m /Pmax)
Answer: B
104. The pitch of threads on a Jock nut in comparison to pitch of nut is
A. Same
B. Coarser
C. Finer
D. Very fine
Answer: A
105. Buttress threads are usually found on
A. Screw cutting lathes
B. Feed mechanisms
C. Spindles of bench vices
D. Railway carriage couplings
Answer: D
106. A tapered key which fits in a key-way in the hub and is flat on the shaft, is known as
A. Woodruff key
B. Feather key
C. Flat saddle key
D. Gib head key
Answer: C
107. Fibrous fracture occurs in
A. Ductile material
B. Brittle material
C. Elastic material
D. Hard material
Answer: A
108. 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
109. Turn buckle has
A. Right hand threads on bout ends
B. Left hand threads on both ends
C. Left hand threads on one end and right hand threads on other end
D. No threads
Answer: C
110. 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
111. The contact ratio is the ratio of
A. Length of arc of recess to the circular pitch
B. Length of path of contact to the circular pitch
C. Length of arc of contact to the circular pitch
D. Length of arc of approach to the circular pitch
Answer: C
112. Elastic nut is a locking device in which
A. One small 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. Hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed 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 pin splitted and bent in reverse direction at other end
Answer: C
113. 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
114. Which of the following statement is correct?
A. The stress concentration in static loading is more serious in ductile materials and less serious in brittle materials
B. The stress concentration in static loading is more serious in brittle materials and less serious in ductile materials
C. The toughness of a material increases when it is heated
D. The shear stress in a beam varies from zero at the neutral surface and maximum at the outer fibres
Answer: B
115. 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
116. Taper usually provided on cotter is
A. 1 in 5
B. 1 in 10
C. 1 in 24
D. 1 in 40
Answer: C
117. The condition for maximum power transmission is that the maximum tension in the flat belt should be equal to
(Where, Pc = tension in belt due to centrifugal force)
A. 3 Pc
B. Pc
C. Pc/3
D. 2 Pc
Answer: A
118. Applications in which stresses are encountered in one direction only uses following type of threads
A. Metric
B. Buttress
C. Acme
D. Square
Answer: B
119. The draw of cotter need not exceed
A. 3 mm
B. 5 mm
C. 10 mm
D. 20 mm
Answer: A
120. A bench vice has following type of threads
A. Metric
B. Square
C. Buttress
D. Acme
Answer: D
121. 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
122. Which of the following statement is wrong?
A. The V-belt may be operated in either direction with tight side of the belt at the top or bottom
B. The V-belt drive is used with large center distance
C. The power transmitted by V-belts is less than flat belts for the same coefficient of friction, arc of contact and allowable tension in the belts
D. The ratio of driving tensions in V-belt drive is more than flat belt drives
Answer: B
123. 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
124. Silver based solder is used for
A. Flaring
B. Brazing
C. Soft soldering
D. Fusion welding
Answer: B
125. For tight leakage joints, following type of thread is best suited
A. Metric
B. Buttress
C. Square
D. NPT (national pipe threads).
Answer: D
126. 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
127. 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
128. In order to permit the thermal expansion/contraction of tubing, it should be
A. Crimped
B. Honed
C. Flared
D. Bent
Answer: D
129. 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
130. The strap end of a connecting rod of steam engine is joined by
A. Gib of cotter joint
B. Sleeve and cotter joint
C. Spigot socket cotter joint
D. Knuckle joint
Answer: A
131. When a bolt is subjected to shock loading, the resilience of the bolt should be considered in order to prevent breakage at the
A. Thread
B. Middle
C. Shank
D. Head
Answer: A
132. 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
133. 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
134. The suitable material for belt in agricultural machinery is
A. Leather
B. Rubber
C. Cotton duck
D. Balata gum
Answer: B
135. The shear plane in case of bolts should
A. Be across threaded portion of shank
B. Be parallel to axis of bolt
C. Be normal to threaded portion of shank
D. Never be across the threaded portion
Answer: D
136. The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80° for
A. Reducing stress concentration
B. Ease of manufacture
C. Safety
D. Fullering and caulking
Answer: D
137. The piston rod of a steam engine is usually connected to the cross-head by means of
A. Bolted joint
B. Knuckle joint
C. Cotter joint
D. Universal joint
Answer: C
138. The ratio of endurance limit in shear to the endurance limit in flexure is
A. 0.70
B. 0.25
C. 0.40
D. 0.55
Answer: D
139. Which of the following pipe joints would be suitable for pipes carrying steam?
A. Flanged
B. Threaded
C. Bell and spigot
D. Expansion
Answer: D
140. When the belt speed increases
A. Power transmitted increases
B. Power transmitted decreases
C. Power transmitted increases to a maximum value and then decreases
D. Power transmitted remains the same
Answer: C
141. Spring index is
A. Ratio of coil diameter to wire diameter
B. Load required to produce unit deflection
C. Its capability of storing energy
D. Indication of quality of spring
Answer: A
142. If a bearing is designated by the number 305, it means that the bearing is of
A. Medium series whose bore is 5 mm
B. Medium series whose bore is 25 mm
C. Light series whose bore is 25 mm
D. Light series whose bore is 5 mm
Answer: B
143. The shearing stresses in the inner face as compared to outer face of the wire in a heavy close coiled spring is
A. Larger
B. Smaller
C. Equal
D. Larger/smaller depending on diameter of spring coil
Answer: A
144. The metal suitable for bearings subjected to heavy loads is
A. White metal
B. Silicon bronze
C. Monel metal
D. Phosphor bronze
Answer: A
145. Form coefficient of spring is
A. Ratio of coil diameter to wire diameter
B. Load required to produce unit deflection
C. Its capability of storing energy
D. Concerned with strength of wire of spring
Answer: C
146. 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
147. 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
148. 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
149. When a close coiled helical spring is compressed, its wire is subjected to
A. Tension
B. Shear
C. Compression
D. All of the above
Answer: A
150. A bolt of uniform strength can be developed by
A. Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
B. Keeping the core diameter smaller than the diameter of the unthreaded portion
C. Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
D. None of the above
Answer: A
151. When the bearing is subjected to large fluctuations of load and heavy impacts, the bearing characteristic number should be _________ the bearing modulus.
A. 10 times
B. 5 times
C. 15 times
D. 20 times
Answer: C
152. Which is positive drive?
A. Flat belt drive
B. V belt drive
C. Crossed belt drive
D. Timing belt
Answer: D
153. If two springs are in parallel then their overall stiffness will be
A. Half
B. Same
C. Double
D. None of the above
Answer: C
154. In hydrodynamic 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
155. A sliding bearing which operates without any lubricant present, is called
A. Zero film bearing
B. Boundary lubricated bearing
C. Hydrodynamic lubricated bearing
D. Hydrostatic lubricated bearing
156. The bearings of heavy series have capacity __________ over the medium series.
A. 20 to 30%
B. 10 to 20%
C. 30 to 40%
D. 40 to 50%
Answer: A
157. Antifriction bearings are
A. Sleeve bearings
B. Hydrodynamic bearings
C. Thin lubricated bearings
D. None of the above
Answer: D
158. 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
A. ZN/p
B. p/ZN
C. Z/pN
D. N/Zp
Answer: A
159. Euler’s formula for a mild steel column is not valid if the slenderness ratio is
A. 90
B. 60
C. 120
D. 100
Answer: B
160. A screw is said to be over hauling screw, if its efficiency is
A. More than 50%
B. Less than 50%
C. Equal to 50%
D. None of these
Answer: A
161. 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
162. 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
163. For hardening alloy steels and high speed steels, they are heated to
A. 1100 to 1300°C
B. 1300 to 1500°C
C. 500 to 600°C
D. 700 to 900°C
Answer: A
164. 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
165. The rated life of a bearing varies
A. Directly as load
B. Inversely as square of load
C. Inversely as cube of load
D. Inversely as fourth power of load
Answer: C
166. 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: C
167. Three different weights fall from a certain height under vacuum. They will take
A. Same time to reach earth
B. Times proportional to weight to reach earth
C. Times inversely proportional to weight to reach earth
D. None of the above
Answer: A
168. 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
169. In cross or regular lay ropes
A. Direction of twist of wires in strands is opposite to the direction of twist of strands
B. Direction of twist of wires and strands are same
C. Wires in two adjacent strands are twisted in opposite direction
D. Wires are not twisted
Answer: A
170. A universal coupling is used to connect two shafts
A. Which are not in exact alignment
B. Which are perfectly aligned
C. Whose axes intersect at a small angle
D. Have lateral misalignment
Answer: C
171. In standard taper roller bearings, the angle of taper of outer raceway is
A. 5°
B. 8°
C. 15°
D. 25°
Answer: D
172. In composite or reverse laid ropes
A. Direction of twist of wires in strands is opposite to the direction of twist of strands
B. Direction of twist of wires and strands are same
C. Wires in two adjacent strands are twisted in opposite direction
D. Wires are not twisted
Answer: C
173. Whether any core is required in wire ropes
A. Yes
B. No
C. Sometimes
D. Rarely
Answer: A
174. The lower deviation is the algebraic difference between the
A. Actual size and the corresponding basic size
B. Maximum limit and the basic size
C. Minimum limit and the basic size
D. None of the above
Answer: C
175. If shearing stress in nut is half the tensile stress in a bolt, then nut length should be equal to
A. Diameter of bolt
B. 0.75 × diameter of bolt
C. 1.25 × diameter of bolt
D. 1.5 × diameter of bolt
Answer: A
176. 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
177. The maximum normal stress theory is used for
A. Plastic materials
B. Brittle materials
C. Non-ferrous materials
D. Ductile materials
Answer: B
178. The rivet head used for boiler plate riveting is usually
A. Pan Head
B. Snap head
C. Counter sunk head
D. Conical head
Answer: B
179. Basic hole 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: B
180. I.S. specifies following total number of grades of tolerances
A. 18
B. 16
C. 20
D. 22
Answer: A
181. 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
182. The number of slots in a 25 mm castle nut is
A. 8
B. 4
C. 2
D. 6
Answer: D
183. Which of the following material has the maximum ductility?
A. Copper
B. Mild steel
C. Aluminium
D. Zinc
Answer: B
184. The included angle for the British Association thread is
A. 29°
B. 55°
C. 47.3°
D. 60°
Answer: B
185. An open belt drive is used when
A. Shafts are arranged at right angles and rotate in one definite direction
B. Shafts are arranged parallel and rotate in the opposite directions
C. Shafts are arranged parallel and rotate in the same directions
D. Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
Answer: C
186. Screws used for power transmission should have
A. Low efficiency
B. High efficiency
C. Very fine threads
D. Strong teeth
Answer: B
187. The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be
A. Same in both cases
B. 2 times more
C. 3 times more
D. 4 times more
Answer: C
188. The fatigue life of a part can be improved by
A. Electroplating
B. Polishing
C. Coating
D. Shot peening
Answer: D
189. 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
190. The application of third type levers is found in
A. Handle of a hand pump
B. Hand wheel of a punching press
C. Lever of a loaded safety valve
D. A pair of tongs
Answer: D
191. In case of V belt drive
A. The belt should touch the bottom of groove in the pulley
B. The belt should not touch the bottom of groove in the pulley
C. The belt should not touch the sides of groove in the pulley
D. None of the above
Answer: B
192. Which is correct statement? Stress concentration in cyclic loading is
A. Very serious in brittle materials and less serious in ductile materials
B. Very serious in ductile materials and less serious in brittle materials
C. Equally serious in both types of materials
D. Seriousness would depend on other factors
Answer: C
193. 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
194. In testing a material for endurance strength, it is subjected to
A. Static load
B. Dynamic load
C. Impact load
D. Completely reversed load
Answer: D
195. If a material fails below its yield point, failure would be due to
A. Straining
B. Fatigue
C. Creep
D. Sudden loading
Answer: B
196. In leaf springs, the longest leaf is known as
A. Master leaf
B. Lower leaf
C. Upper leaf
D. None of these
Answer: A
197. For same pulley diameters, center distance, belt speed and belt and pulley materials,
A. Open belt drive transmits more power than crossed belt drive
B. Crossed belt drive transmits more power than open belt drive
C. Open and crossed belt drives transmit same power
D. Power transmission does not depend upon open and crossed types of constructions
Answer: B
198. 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
199. When two helical springs of equal lengths are arranged to form a cluster spring, then
A. Shear stress in each spring will be equal
B. Load taken by each spring will be half the total load
C. Only A is correct
D. Both A and B is correct
Answer: D
200. Resistance to fatigue of a material is measured by
A. Young’s modulus
B. Coefficient of elasticity
C. Elastic limit
D. Endurance limit
Answer: D
201. The crest diameter of a screw thread is same as
A. Major diameter
B. Minor diameter
C. Pitch diameter
D. Core diameter
Answer: A
202. A localized compressive stress at the area of contact between two members is known as
A. Bending stress
B. Shear stress
C. Tensile stress
D. Bearing stress
Answer: D
203. The objective of ‘crowning’ of the flat pulleys of belt drive is to
A. Prevent the belt from running off the pulley
B. Increase the power transmission capacity
C. Increase the belt velocity
D. Prevent the belt joint from damaging the belt surface
Answer: A
204. Maximum principal stress theory is applicable for
A. Ductile materials
B. Brittle materials
C. Elastic materials
D. All of the above
Answer: B
205. The following type of nut is used with alien bolt
A. Hexagonal nut
B. Slotted nut
C. Castle nut
D. Any one of the above
Answer: D
206. The standard length of the shaft is
A. 6 m
B. 5 m
C. 7 m
D. All of these
Answer: D
207. 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
208. A self locking screw has
A. Fine threads
B. Course threads
C. Coefficient of friction is greater than tangent of load angle
D. Hole for inserting split pin
Answer: C
209. The included angle between the sides of V-belt is
A. 40°
B. 45°
C. 38°
D. 60°
Answer: A
210. 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
211. In order to obtain bolt of uniform strength
A. Increase shank diameter
B. Increase its length
C. Drill an axial hole through head up to threaded portion so that shank area is equal to root area of thread
D. Tighten die bolt properly
Answer: C
212. The wire ropes make contact at
A. Bottom of groove of the pulley
B. Sides and bottom of groove of the pulley
C. Anywhere in the groove of the pulley
D. Sides of groove of the pulley
Answer: A
213. A key capable of tilting in a recess milled out in a shaft is known as
A. Woodruff key
B. Feather key
C. Flat saddle key
D. Hollow saddle key
Answer: A
214. A key made from a cylindrical disc having segmental cross-section, is known as
A. Woodruff key
B. Feather key
C. Flat saddle key
D. Gib head key
Answer: A
215. 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
216. 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
217. The valve rod in a steam engine is connected to an eccentric rod by
A. Cotter joint
B. Bolted joint
C. Knuckle joint
D. Universal coupling
Answer: C
218. Split 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 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 pin splitted and bent in reverse direction at the other end
Answer: B
219. Fabric belts are used in industrial applications because
A. They are cheap
B. They can work at high temperature
C. They are unaffected by moisture and humidity
D. None of the above
Answer: A
220. Taper on the cotter and slot is provided
A. On both the sides
B. On one side only
C. On none of the sides
D. May be provided anywhere
Answer: B
221. Castle 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 is 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 pin spitted and bent in reverse direction at other end
Answer: D
222. The suitable material for belt used in flour mill is
A. Leather
B. Rubber
C. Canvas or cotton duck
D. Balata gum
Answer: C
223. When a nut is tightened by placing a washer below it, the bolt will be subjected to following type of loads
A. Compression
B. Tension
C. Shear
D. Combined loads
Answer: B
224. Gear box is used
A. To produce torque
B. For speed reduction
C. To obtain variable speeds
D. To increase efficiency of system
Answer: C
225. In order to remove internal stresses produced by hardening the steel, the process usually adopted is
A. Tempering
B. Normalizing
C. Annealing
D. Spheroidizing
Answer: A
226. If a spring is cut down into two springs, the stiffness of cut springs will be
A. Half
B. Same
C. Double
D. None of the above
Answer: C
227. When carbon in the cast iron is principally in the form of graphite, the cast iron will be of
A. Brown colour
B. Yellow colour
C. White colour
D. Grey colour
Answer: D
228. Belt slip may occur due to
A. Heavy load
B. Loose belt
C. Driving pulley too small
D. All of the above
Answer: D
229. The coefficient of friction in belt drive depends upon
A. Material of belt
B. Material of pulley
C. Materials of belt and pulley
D. Belt velocity
Answer: C
230. Aircraft body is usually fabricated by
A. Welding
B. Pre-casting
C. Riveting
D. Casting
Answer: C
231. The resistance to fatigue of a material is measured by
A. Elastic limit
B. Ultimate tensile strength
C. Young’s modulus
D. Endurance limit
Answer: D
232. 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
233. 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
234. In second type of levers,
A. Load is in between the fulcrum and effort
B. Effort is in between the fulcrum and load
C. Fulcrum is in between the load and effort
D. None of these
Answer: A
235. In V-belt drive, belt touches
A. At bottom
B. At sides only
C. Both at bottom and sides
D. Could touch anywhere
Answer: B
236. 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
237. 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
238. 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
239. 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
240. 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
241. The ratio of driving tensions for flat belts, neglecting centrifugal tension, is (where T₁, and T₂ = Tensions on the tight and slack sides of belt respectively, μ = Coefficient of friction, between the belt and pulley, and θ = Angle of contact)
A. T₁/T₂ = μθ
B. log (T₁/T₂) = μθ
C. T₁/T₂ =eμθ
D. T₁/T₂ = log μθ
Answer: C
242. If the centre distance of the mating gears having involute teeth is increased, then the pressure angle
A. Increases
B. Decreases
C. Remains unchanged
D. None of these
Answer: A
243. An open coiled helical compression spring ‘A’ of mean diameter 50 mm is subjected to an axial load ‘W’. Another spring ‘B’ of mean diameter 25 mm is similar to spring ‘A’ in all respects. The deflection of spring ‘B’ will be __________ as compared to spring ‘A’.
A. One-eighth
B. One-fourth
C. One-half
D. Double
Answer: A
244. According to Indian standard specifications, a Grey cast iron designated by ‘FG 200’ means that the
A. Carbon content is 2%
B. Maximum compressive strength is 200 N/mm²
C. Minimum tensile strength is 200 N/mm²
D. Maximum shear strength is 200 N/mm²
Answer: C
245. A bolt is designed on the basis of __________ with a large factor of safety.
A. Direct tensile stress
B. Direct compressive stress
C. Direct bending stress
D. Direct shear stress
Answer: A
246. While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as
A. Both the ends fixed
B. Both the ends hinged
C. One end fixed and the other end hinged
D. One end fixed and the other end free
Answer: D
247. In a butt welded joint, the size of weld is __________ the throat of weld.
A. 0.5 times
B. Equal to
C. 2 times
D. Double
Answer: B 8. 9. 10. 11. 12.
248. According to I.B.R., when the thickness of the boiler shell (t) is less than 8 mm, then the diameter of the 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: C
249. A feather key is generally
A. Loose in shaft and tight in hub
B. Tight in shaft and loose in hub
C. Tight in both shaft and hub
D. Loose in both shaft and hub
Answer: B
250. The process which improves the machinability of steels, but lowers the hardness and tensile strength is
A. Normalising
B. Full annealing
C. Process annealing
D. Spheroidising
Answer: D
251. The acme threads are usually found on
A. Spindles of bench vices
B. Railway carriage couplings
C. Feed mechanism of machine tools
D. Screw cutting lathes
Answer: D
252. A double fillet welded joint with parallel fillet weld of length ‘l’ and leg ‘s’ is subjected to a tensile force ‘P’. Assuming uniform stress distribution, the shear stress in the weld is given by
A. √2P/s.l
B. P/2.s.l
C. P/√2.s.l
D. 2P/s.l
Answer: C
253. The included angle for the V-belt is usually
A. 10°-20°
B. 30°-40°
C. 40°-60°
D. 60°-80°
Answer: B
254. The width of the pulley should be __________ width of the belt.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer: C
255. A key way lowers
A. The strength of the shaft
B. The rigidity of the shaft
C. Both the strength and rigidity of the shaft
D. The ductility of the shaft
Answer: C
256. The form factor of a helical gear __________ with the increase in the helix angle.
A. Increases
B. Decreases
C. Remains constant
D. None of these
Answer: A
257. For a bevel gear having the pitch angle θ, the ratio of formative number of teeth (TE) to actual number of teeth (T) is
A. 1/sinθ
B. 1/cosθ
C. 1/tanθ
D. sinθ cosθ
Answer: B
258. Which of the following has threads at both ends?
A. Bolt
B. Tap bolt
C. Stud
D. None of these
Answer: C
259. The connecting rod bolts are tightened up so that tightening stress
A. Is just sufficient to hold parts together
B. Approaches yield point
C. Is 50% of yield point
D. Is about yield point divided by safety factor
Answer: B
260. The circumferential and longitudinal strains in a cylindrical boiler under internal steam pressure are εc and εl respectively. The change in volume of the boiler cylinder per unit volume will be
A. εc + 2εl
B. 2εc + εl
C. εc + εl²
D. εc² + εl
Answer: B
261. The material used for brake lining should have __________ coefficient of friction.
A. Low
B. High
C. Moderate
D. None of these
Answer: B
262. 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
263. Which of the following spring is used in mechanical wrist watch?
A. Helical compression spring
B. Spiral spring
C. Torsion spring
D. Belleville spring
Answer: C
264. The effective stress in wire ropes during normal working is equal to the stress due to
A. Axial load plus stress due to bending
B. Acceleration/retardation of masses plus stress due to bending
C. Axial load plus stress due to acceleration/retardation
D. Bending plus stress due to acceleration/retardation
Answer: A
265. In levers, leverage is the ratio of
A. Load lifted to the effort applied
B. Mechanical advantage to the velocity ratio
C. Load arm to the effort arm
D. Effort arm to the load arm
Answer: D
266. A special case of ductility which permits materials to be rolled or hammered into thin sheets, is called
A. Plasticity
B. Elasticity
C. Ductility
D. Malleability
Answer: D
267. Wahl’s stress factor __________ very rapidly as the spring index decreases.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer: A
268. When an open coiled helical compression spring is subjected to an axial compressive load, the maximum shear stress induced in the wire is (where D = Mean diameter of the spring coil, d = Diameter of the spring wire, K = Wahl’s stress factor, and W = Axial compressive load on the spring)
A. (WD/ πd3) × K
B. (2WD/ πd3) × K
C. (4WD/ πd3) × K
D. (8WD/ πd3) × K
Answer: D
269. 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
270. In a marine flange coupling, the pitch circle diameter of bolts is taken as
A. 1.2 d
B. 1.6 d
C. 2 d
D. 2.5 d
Answer: B
271. The helix angle for double helical gears may be made up to
A. 45°
B. 60°
C. 75°
D. 90°
Answer: A
272. The bending moment ‘M’ and a torque ‘T’ is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then ‘M’ is equal to
A. T/2
B. T
C. 2 T
D. 4 T
Answer: A
273. 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
274. 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
275. In designing a flange coupling, the pitch circle diameter of bolts is taken as (where d = Diameter of the shaft)
A. 2 d
B. 3 d
C. 4 d
D. 5 d
Answer: B
276. 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
277. The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kt as
A. (Kf + 1)/ (Kt + 1)
B. (Kf – 1)/ (Kt – 1)
C. (Kt + 1)/ (Kf + 1)
D. (Kt – 1)/ (Kf – 1)
Answer: B
278. If the centre distance of the mating gears having involute teeth is varied within limits, the velocity ratio
A. Increases
B. Decreases
C. Remains unchanged
D. None of these
Answer: C
279. A type of brake commonly used in motor cars is a
A. Shoe brake
B. Band and block brake
C. Band brake
D. Internal expanding brake
Answer: D
280. Which of the following property is essential for spring materials?
A. Stiffness
B. Ductility
C. Resilience
D. Plasticity
Answer: C
281. 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
282. The bending stress in a curved beam is
A. Zero at the centroidal axis
B. Zero at the point other than centroidal axis
C. Maximum at the neutral axis
D. None of these
Answer: B
283. 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
284. In the levers of third type, the mechanical advantage is __________ one.
A. Less than
B. Equal to
C. More than
D. None of these
Answer: A
285. The maximum efficiency of a square threaded screw is
A. (1 – sinφ)/ (1 + sinφ)
B. (1 + sinφ)/ (1 – sinφ)
C. (1 – sinφ)/ (1 + cosφ)
D. (1 + cosφ)/ (1 – sinφ)
Answer: A
286. 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
287. 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
288. 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
289. Oldham coupling is used to connect two shafts
A. Which are perfectly aligned
B. Which are not in exact alignment
C. Which have lateral misalignment
D. Whose axes intersect at a small angle
Answer: C
290. The size of a cam depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Pitch curve
Answer: A
291. 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
292. When a material is subjected to fatigue loading, the ratio of the endurance limit to the ultimate tensile strength is
A. 0.20
B. 0.35
C. 0.50
D. 0.65
Answer: C
293. A hollow saddle key is
A. A taper key which fits half in the key way of hub and half in the key way of shaft
B. A taper key which fits in a key way of the hub and is flat on the shaft
C. A taper key which fits in a key way of the hub and the bottom of the key is shaped to fit the curved surface of the shaft
D. Provided in pairs at right angles and each key is to withstand torsion in one direction only
Answer: C
294. A tapered key which fits in a key way in the hub and the bottom of which is shaped to fit the curved surface of the shaft, is known as,
A. Hollow saddle key
B. Hollow key
C. Soft key
D. None of these
Answer: A
295. When the length of the journal is equal to the diameter of the journal, then the bearing is said to be a
A. Short bearing
B. Long bearing
C. Medium bearing
D. Square bearing
Answer: D
296. 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
297. Two closely coiled helical springs with stiffness k₁ and k₂ respectively are connected in series. The stiffness of an equivalent spring is given by
A. (k₁ k₂)/ (k₁ + k₂)
B. (k₁ – k₂)/ (k₁ + k₂)
C. (k₁ + k₂)/ (k₁ k₂)
D. (k₁ – k₂)/ (k₁ k₂)
Answer: A
298. The cross-section of the arm of a bell crank lever is
A. Rectangular
B. Elliptical
C. I-section
D. Any one of these
Answer: D
299. Two shafts ‘A’ and ‘B’ under pure torsion are of identical length and identical weight and are made of the same material. The shaft ‘A’ is solid and the shaft ‘B’ is hollow. We can say that
A. Shaft B is better than shaft A
B. Shaft A is better than shaft B
C. Both the shafts are equally good
D. None of these
Answer: A
300. 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
301. 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
302. 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
303. A steel containing _________ 0.8% carbon is known as hypo-eutectoid steel.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer: B
304. The material commonly used for crane hooks is
A. Cast iron
B. Wrought iron
C. Mild steel
D. Aluminium
Answer: B
305. 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
306. The velocity factor for very accurately cut and ground metallic gears operating at velocities upto __________ are equal to 6/(6 + v).
A. 10 m/s
B. 12.5 m/s
C. 15 m/s
D. 20 m/s
Answer: D
307. When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
A. 4F/ πd²
B. 6F/ πd²
C. 8F/ πd²
D. 16F/ 3πd²
Answer: D
308. According to Indian standards, total numbers of fundamental deviations are
A. 10
B. 15
C. 20
D. 25
Answer: D
309. The most important dimension in the design of a nut is
A. Pitch diameter
B. Inside diameter
C. Outside diameter
D. Height
Answer: D
310. When an open coiled helical compression spring is subjected to an axial compressive load, the stress induced in the wire is
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Bending stress
Answer: C
311. If T₁ and T₂ are the tensions on the tight and slack sides of the belt respectively, and Tc is the centrifugal tension, then initial tension in the belt is equal to
A. T₁ – T₂ + Tc
B. T₁ + T₂ + Tc
C. (T₁ – T₂ + Tc)/2
D. (T₁ + T₂ + Tc)/2
Answer: D
312. 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
313. Cast iron pipes are mainly used
A. For conveying steam
B. In water and sewage systems
C. In pressure lubrication systems on prime movers
D. All of the above
Answer: B
314. The modulus of elasticity for mild steel is approximately equal to
A. 80 kN/mm²
B. 100 kN/mm²
C. 110 kN/mm²
D. 210 kN/mm²
Answer: D
315. If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited
A. Square
B. Acme
C. Buttress
D. BSW
Answer: C
316. The stress in the threaded part of the bolt will be __________ as compared to the shank.
A. Same
B. Higher
C. Lower
D. None of these
Answer: B
317. In designing a connecting rod, it is considered like __________ for buckling about Y-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: B
318. For a square key made of mild steel, the shear and crushing strength are related as
A. Shear strength is equal to crushing strength
B. Shear strength is greater than crushing strength
C. Shear strength is less than crushing strength
D. None of the above
Answer: A
318. In thrust bearings, the load acts
A. Along the axis of rotation
B. Parallel to the axis of rotation
C. Perpendicular to the axis of rotation
D. In any direction
Answer: A
319. When compared to the rod of the same diameter and material, a wire rope
A. Is less flexible
B. Has a much smaller load carrying capacity
C. Does not provide much warning before failure
D. Provides much greater time for remedial action before failure
Answer: B
320. 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
321. Lewis form factor for 14½° composite and full depth involute system is (where T = Number of teeth)
A. 0.124 – (0.684/T)
B. 0.154 – (0.912/T)
C. 0.175 – (0.841/T)
D. None of these
Answer: A
322. Which of the following statement is correct?
A. The distance from a point on one thread to the corresponding point on the next thread is called pitch
B. The distance which a screw thread advances axially in one rotation of the nut is called lead
C. In single start threads, lead is equal to pitch
D. All of the above
Answer: D
323. 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
324. When a beam of rectangular cross-section of width b and depth d, is subjected to a shear force F, the maximum shear stress induced will be
A. F/bh
B. 3F/2bh
C. 2F/bh
D. 4F/bh
Answer: B
325. The endurance or fatigue limit is defined as the maximum value of the stress which a polished standard specimen can withstand without failure, for infinite number of cycles, when subjected to
A. Static load
B. Dynamic load
C. Static as well as dynamic load
D. Completely reversed load
Answer: D
326. Two shafts will have equal strength, if
A. Diameter of both the shafts is same
B. Angle of twist of both the shafts is same
C. Material of both the shafts is same
D. Twisting moment of both the shafts is same
Answer: D
327. The pitch diameter is the __________ diameter of an external or internal screw thread.
A. Effective
B. Smallest
C. Largest
D. None of these
Answer: A
327. The efficiency of a square threaded screw is maximum if the helix angle is equal to
(Where φ = Angle of friction)
A. 90° – φ
B. 45° – φ
C. 45° – φ/2
D. 45° + φ/2
Answer: C
328. The efficiency of a square threaded screw is maximum if the helix angle is equal to
(Where φ = Angle of friction)
A. (1/2) × √(σ² + 4τ²)
B. √(σ² + 4τ²)
C. (1/2) × [σ + √(σ² + 4τ²)]
D. σ + √(σ² + 4τ²)
Answer: A
329. When two non-intersecting and non-coplanar shafts are connected by gears, the arrangement is known as
A. Spur gearing
B. Helical gearing
C. Bevel gearing
D. Spiral gearing
Answer: D
330. The ratio of driving tensions in V-belt drives is __________ flat belt drives.
A. Equal to
B. sin α times more than
C. sin α times less than
D. cosec α times more than
Answer: D
331. 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
332. A screw is said to be over hauling screw, if the
A. Friction angle is less than helix angle
B. Friction angle is more than helix angle
C. Friction angle is equal to helix angle
D. Efficiency of screw is 100%
Answer: A
333. 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
334. In a partial journal bearing, the angle of contact of the bearing with the journal is
A. 120°
B. 180°
C. 270°
D. 360°
Answer: A
335. In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)
A. T₁/T₂ = μθ × n
B. T₁/T₂ = (μθ)n
C. T₁/T₂ = [(1 – μ tanθ)/ (1 + μ tanθ)]n
D. T₁/T₂ = [(1 + μ tanθ)/ (1 – μ tanθ)]n
Answer: D
336. In a flat belt drive, if the slip between the driver and belt is 1 %, between the belt and follower is 3% and driver and follower pulley diameters are equal, then velocity ratio of the drive will be
A. 0.96
B. 0.97
C. 0.98
D. 0.99
Answer: A
337. 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
338. Rankine’s theory is used for
A. Brittle materials
B. Ductile materials
C. Elastic materials
D. Plastic materials
Answer: A
339. Wire ropes as compared to cotton ropes
A. Are lighter in weight
B. Offer silent operation
C. Can withstand shock loads
D. All of these
Answer: D
340. A connecting rod subjected to an axial load may buckle with
A. X-axis as neutral axis
B. Y-axis as neutral axis
C. X-axis or Y-axis as neutral axis
D. Z-axis
Answer: C
341. Two shafts A and B are made of the same material. The diameter of shaft A is twice as that of shaft B. The power transmitted by the shaft A will be __________ of shaft B.
A. Twice
B. Four times
C. Eight times
D. Sixteen times
Answer: C
342. The material commonly used for machine tool bodies is
A. Mild steel
B. Aluminium
C. Brass
D. Cast iron
Answer: D
343. For longitudinal 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: B
344. In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called
A. Normal pitch
B. Axial pitch
C. Diametral pitch
D. Module
Answer: A
345. The minimum number of teeth on the pinion which will mesh with any gear without interference for 20° full depth involute teeth will be
A. 12
B. 14
C. 18
D. 24
Answer: C
346. 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
347. According to Rankine’s theory, the failure occurs at a point in a member
A. When the maximum shear stress in a biaxial stress system reaches the shear stress at elastic limit in a simple tension test
B. When the maximum principal stress in a biaxial stress system reaches the elastic limit of the material in a simple tension test
C. When the strain energy per unit volume in a biaxial stress system reaches the strain energy at the elastic limit per unit volume as determined from a simple tension test
D. When the maximum principal strain in a biaxial stress system reaches the strain at the elastic limit as determined from a simple tension test
Answer: B
348. Which one of the following loading is considered for the design of axles?
A. Bending moment only
B. Twisting moment only
C. Combined bending moment and twisting moments
D. Combined action of bending moment, twisting moment and axial thrust
Answer: A
349. 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
350. 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
351. The elasticity is the property of a material which enables it to
A. Regains its original shape after deformation when the external forces are removed
B. Draw into wires by the application of a tensile force
C. Resists fracture due to high impact loads
D. Retain deformation produced under load permanently
Answer: A
352. A locking device extensively used in marine type connecting rod ends is a
A. Jam nut
B. Castle nut
C. Sawn nut
D. Ring nut
Answer: D
353. For a shaft diameter of 100 mm, the number of bolts in a flange coupling should be
A. 4
B. 6
C. 8
D. 10
Answer: A
354. When the connected members are very yielding (soft gasket) as compared to the bolt, then the resultant load on the bolt will be equal to the
A. Initial tension
B. External load applied
C. Sum of the initial tension and external load applied
D. Initial tension or external load, whichever is greater
Answer: C
355. The shock absorbing capacity of a bolt can be increased by
A. Tightening it properly
B. Increasing shank diameter
C. Grinding the shank
D. Making shank diameter equal to core diameter of thread
Answer: D
356. According to Unwin’s formula, the relation between the diameter of rivet hole D. and the thickness of plate (t) is given by (where d and t are in mm)
A. d = t
B. d = 1.6 t
C. d = 2 t
D. d = 6 t
Answer: D
357. When two non-parallel or intersecting but coplanar shafts are connected by gears, the arrangement is known as,
A. Bevel gearing
B. Helical gearing
C. Worm gearing
D. None of these
Answer: A
358. 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
358. The process extensively used for making bolts and nuts is
A. Hot piercing
B. Extrusion
C. Cold peening
D. Cold heading
Answer: D
359. What is the answer to this question?
A. 2WD3n/Gd⁴
B. 4WD3n/Gd⁴
C. 8WD3n/Gd⁴
D. 16WD3n/Gd⁴
Answer: C
360. In a steam engine, the piston rod is usually connected to the cross-head by means of a
A. Knuckle joint
B. Cotter joint
C. Oldham coupling
D. Universal joint
Answer: B
361. When a closely coiled helical spring is subjected to a couple about its axis, the stress induced in the wire material of the spring is
A. Bending stress only
B. A combination of torsional shear stress and bending
C. Direct shear stress only
D. A combination of bending stress and direct shear stress
Answer: A
362. In a belt drive, if the pulley diameter is doubled keeping the tension and belt width constant, then it will be necessary to
A. Increase the key length
B. Increase the key depth
C. Increase the key width
D. Decrease the key length
Answer: A
363. In an oil lubricated journal bearing, the coefficient of friction between the journal and the bearing
A. Remains constant at all speeds
B. Is minimum at zero speed and increases monotonically with increase in speed
C. Is maximum at zero speed and decreases monotonically with increase in speed
D. Becomes minimum at an optimum speed and then increases with further increase in speed
Answer: D
364. The largest diameter of an external or internal screw thread is known as
A. Minor diameter
B. Major diameter
C. Pitch diameter
D. None of these
Answer: B
365. For high speed engines, the cam follower should move with
A. Uniform velocity
B. Simple harmonic motion
C. Uniform acceleration and retardation
D. Cycloidal motion
Answer: D
366. The taper on a rectangular sunk key is
A. 1 in 16
B. 1 in 32
C. 1 in 48
D. 1 in 100
Answer: D
368. In designing thick cylinders, the equation used is
A. Lame’s equation
B. Birnie’s equation
C. Clavarinos’ equation
D. All of these
Answer: D
369. 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
370. The ratio of pitch circle diameter in millimeters to the number of teeth, is called
A. Circular pitch
B. Diametral pitch
C. Module
D. None of these
Answer: C
371. A sliding bearing in which although lubricant is present, the working surfaces __________ contact each other at least part of the time, is called boundary lubricated bearing.
A. Partially
B. Fully
C. Either A or B
D. None of these
Answer: A
372. In radial bearings, the load acts __________ to the axis of rotation.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer: B
373. 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
374. 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
375. According to Indian standards, the diameter of rivet hole is made larger than the basic size of rivet by
A. 0.5 mm up to 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
376. The helix angle for single helical gears ranges from
A. 10° to 15°
B. 15° to 20°
C. 20° to 35°
D. 35° to 50°
Answer: C
377. The centre distance between two meshing involute gears is equal to
A. Sum of base circle radii/cosφ
B. Difference of base circle radii/cosφ
C. Sum of pitch circle radii/cosφ
D. Difference of pitch circle radii/cosφ
Answer: A
378. In block brakes, the ratio of shoe width to wheel diameter is taken between
A. 0.1 and 0.25
B. 0.25 and 0.50
C. 0.50 and 0.75
D. 0.75 and 1
Answer: B
379. 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
380. 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
381. 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
382. The property of a material which enables it to be drawn into wires with the application of a tensile force, is called
A. Plasticity
B. Elasticity
C. Ductility
D. Malleability
Answer: C
383. The cold working of metals is carried out __________ the recrystallization temperature.
A. Above
B. Below
C. At
D. None of these
Answer: B
384. The expansion joint is mostly used for pipes which carry steam at __________ pressures.
A. Low
B. High
C. Medium
D. None of these
Answer: B
384. Crushing resistance required to crush the rivet per pitch length is
A. p.d.σc
B. p.t.σc
C. n.d.t.σc
D. (p – d) t.σc
Answer: C
385. The strength of a riveted joint is equal to
A. Tearing strength of plate (Pt)
B. Shearing strength of rivet (Ps)
C. Crushing strength of rivet (Pc)
D. Least value of Pt Ps and Pc
Answer: D
386. The material generally used for aircraft components is
A. Mild steel
B. High speed steel
C. Stainless steel
D. Aluminium
Answer: D
387. In the calculation of induced shear stress in helical springs, the Wahl’s stress factor is used to take care of
A. Combined effect of transverse shear stress and bending stress in the wire
B. Combined effect of bending stress and curvature of the wire
C. Combined effect of transverse shear stress and curvature of wire
D. Combined effect of torsional shear stress and transverse shear stress in the wire
Answer: B
388. 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
389. The static tooth load should be __________ the dynamic load.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer: C
390. 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
391. The efficiency of a riveted joint is equal to
A. Pt /P
B. Ps /P
C. Pc /P
D. Least of Pt, Ps and Pc/P
Answer: D
391. If a shaft made from ductile material is subjected to combined bending and twisting moment, calculations based on which one of the following failure theories will give the most conservative value?
A. Maximum principal stress theory
B. Maximum shear stress theory
C. Maximum strain energy theory
D. Maximum distortion energy theory
Answer: A
392. An elastic bar is fixed at the upper end and loaded at the lower end by a falling weight. The shock load produced can be reduced by
A. Increasing the length of bar
B. Decreasing the cross-sectional area of the bar
C. Decreasing the modulus of elasticity of the bar
D. All of the above
Answer: D
393. A localized 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
394. 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. (π/4) d² × τ × n
B. 1.875 × (π/4) d² × τ × n
C. 2 × (π/4) d² × τ × n
D. 3 × (π/4) d² × τ × n
Answer: B
395. A shaft is subjected to a maximum bending stress of 80 N/mm² and maximum shearing stress equal to 30 N/mm² at a particular section. If the yield point in tension of the material is 280 N/mm² and the maximum shear stress theory of failure is used, then the factor of safety obtained will be
A. 2.5
B. 2.8
C. 3.0
D. 3.5
Answer: B
396. 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
397. 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
398. Two shafts of the same length and material are joined in series. If the ratio of their diameters is 2, then the ratio of their angles of twist will be
A. 2
B. 4
C. 8
D. 16
Answer: D
399. A steel containing 0.8% carbon is known as
A. Eutectoid steel
B. Hypereutectoid steel
C. Hypo-eutectoid steel
D. None of these
Answer: A
400. 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
401. 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
402. 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
403. 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
404. The contact ratio for gears is
A. Zero
B. Less than one
C. Greater than one
D. None of these
Answer: C
405. The gears are termed as medium velocity gears, if their peripheral velocity is
A. 1-3 m/s
B. 3-15 m/s
C. 15-30 m/s
D. 30-50 m/s
Answer: B
406. 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
407. In a multiple V-belt drive, if one of the belts break, then
A. Only the broken belt is replaced
B. The entire set of belts is replaced
C. The broken belt and the belt on either side of it, is replaced
D. The broken belt need not to be replaced
Answer: B
408. A steel containing up to 0.15% carbon is known as
A. Mild steel
B. Dead mild steel
C. Medium carbon steel
D. High carbon steel
Answer: B
409. When a helical compression spring is cut into halves, the stiffness of the resulting spring will be
A. Same
B. Double
C. One-half
D. One-fourth
Answer: B
410. A coupling used to connect two perfectly aligned shafts, is
A. Muff coupling
B. Compression coupling
C. Flange coupling
D. All of these
Answer: D
411. 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
412. A connecting rod is designed as a
A. Long column
B. Short column
C. Strut
D. All of these
Answer: C
413. When bevel gears having equal teeth and equal pitch angles connect two shafts whose axes intersect at right angle, then they are known as
A. Angular bevel gears
B. Crown bevel gears
C. Internal bevel gears
D. Miter gears
Answer: D
414. When the connected members are very yielding (soft gasket) as compared to the bolt, then the resultant load on the bolt will be equal to the
A. Initial tension
B. External load applied
C. Sum of the initial tension and external load applied
D. Initial tension or external load, whichever is greater
Answer: C
415. The property of a bearing material which has the ability to accommodate shaft deflections and bearing inaccuracies by plastic deformation without excessive wear and heating, is known as
A. Bondability
B. Embeddability
C. Comformability
D. Fatigue strength
Answer: C
416. The shock resistance of steel is increased by adding
A. Nickel
B. Chromium
C. Nickel and chromium
D. Cobalt and molybdenum
Answer: C
417. 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
418. For general industrial machinery, the ratio of the length of journal to its diameter is taken as
A. 0.5 to 1
B. 1 to 2
C. 3 to 5
D. 5 to 10
Answer: B
419. In order to ensure self locking in a screw jack, it is essential that helix angle is __________ friction angle.
A. Larger than
B. Smaller than
C. Equal to
D. None of these
Answer: B
420. Which of the following key is preferred for the condition when a large amount of impact type torque is to be transmitted in both direction of rotation?
A. Woodruff key
B. Feather key
C. Gib-head key
D. Tangent key
Answer: D
421. The washer is generally specified by its
A. Outer diameter
B. Hole diameter
C. Thickness
D. Mean diameter
Answer: B
422. 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. 2 d
D. 2.5 d
Answer: C
423. The product of the diametral pitch and circular pitch is equal to
A. 1
B. 1/π
C. π
D. π × number of teeth
Answer: C
424. In order to have a connecting rod equally strong in buckling about X-axis and Y-axis, the moment of inertia about X-axis should be __________ the moment of inertia about Y-axis.
A. Equal to
B. Twice
C. Three times
D. Four times
Answer: D
425. In a boundary lubricated bearing, there is a __________ of lubricant between the journal and the bearing.
A. Thick film
B. Thin film
C. Either A or B
D. None of these
Answer: B
426. Tearing resistance required to tear off the plate per pitch length is (where p = Pitch of rivets, d = Dia. of rivet hole, and σt = Permissible tensile stress for plate material)
A. p.d.σt
B. p.t.σt
C. (p – d) σt
D. (p – d) t.σt
Answer: D
427. According to Indian standards, total numbers of tolerance grades are
A. 8
B. 12
C. 18
D. 20
Answer: C
428. 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
430. A plate with an elliptical hole in the centre, with semi-major axis A. perpendicular to the direction of loading and semi-minor axis B. along the direction of loading, is subjected to a pull P. The maximum stress induced at the edge of the hole is equal to (where σ = Stress for a plate with no hole i.e. nominal stress)
A. σ [1 + (b/2a)]
B. σ [1 + (2a/b)]
C. σ [1 + (b/3a)]
D. σ [1 + (3a/b)]
Answer: B
431. In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.
A. Right hand
B. Left hand
C. Both A and B
D. None of these
Answer: B
432. Which of the following statement is correct?
A. A parallel sunk key is a taperless key
B. A parallel sunk key may be rectangular or square in cross-section
C. A flat saddle key is a taper key which fits in a key way of the hub and is flat on the shaft
D. All of the above
Answer: D
433. The ratio of the ultimate stress to the design stress is known as
A. Elastic limit
B. Strain
C. Factor of safety
D. Bulk modulus
Answer: C
434. A shaft is subjected to fluctuating loads for which the normal torque (T) and bending moment (M) are 1000 N-m and 500 N-m respectively. If the combined shock and fatigue factor for bending is 1.5 and combined shock and fatigue factor for torsion is 2, then the equivalent twisting moment for the shaft is
A. 2000 N-m
B. 2050 N-m
C. 2100 N-m
D. 2136 N-m
Answer: D
435. 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
436. 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
437. The plasticity is the property of a material which enables it to
A. Regain its original shape after deformation when the external forces are removed
B. Draw into wires by the application of a tensile force
C. Resist fracture due to high impact loads
D. Retain deformation produced under load permanently
Answer: D
438. In a journal bearing, the load on the bearing is __________ to the axis of the journal.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer: B
439. Which of the following cotter joint will be used to connect strap end of a connecting rod?
A. Spigot and socket cotter joint
B. Sleeve and cotter joint
C. Gib and cotter joint
D. Any one of these
Answer: C
440. The fatigue stress concentration factor is defined as
A. The ratio of endurance limit with stress concentration to the endurance limit without stress concentration
B. The ratio of endurance limit without stress concentration to the endurance limit with stress concentration
C. The product of the endurance limits with and without stress concentration
D. All of the above
Answer: B
441. 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
442. 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
443. The coefficient of friction between the belt and pulley depends upon the
A. Material of belt and pulley
B. Slip of belt
C. Speed of belt
D. All of these
Answer: D
444. The steel pulleys are __________ in weight than cast iron pulleys of the same capacity.
A. Heavier
B. Lighter
C. Moderate
D. None of these
Answer: B
445. Margin
B. Pitch
C. Back pitch
D. Diagonal pitch
Answer: B
446. 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
447. A crankshaft is a __________ shaft.
A. Transmission
B. Machine
C. Machine frame
D. None of these
Answer: B
448. In designing a sleeve coupling, length of the sleeve is taken as (where d = Diameter of the shaft)
A. d + 17 mm
B. 2d + 13 mm
C. 2d + 20 mm
D. 3.5 d
Answer: D
449. The maximum shear stress theory is used for
A. Brittle materials
B. Ductile materials
C. Plastic materials
D. Nonferrous materials
Answer: B
450. A circular shaft can transmit a torque of 5 kN-m. If the torque is reduced to 4 kN-m, then the maximum value of bending moment that can be applied to the shaft is
A. 1 kN-m
B. 2 kN-m
C. 3 kN-m
D. 4 kN-m
Answer: C
451. In worm, gears, pitch lead angle is
A. Half the angle between two inclined faces in axial plane
B. The angle between the tangent to the pitch helix and the plane of rotation
C. The angle between the tangent to the pitch helix and an element of the cylinder
D. None of the above
Answer: B
452. 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
453. 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
454. The spring mostly used in gramophones is
A. Helical spring
B. Conical spring
C. Flat spiral spring
D. Volute spring
Answer: C
455. The maximum bending stress in a curved beam having symmetrical section always occur at the
A. Centroidal axis
B. Neutral axis
C. Inside fiber
D. Outside fiber
Answer: C
456. In a flange coupling, the bolts are subjected to
A. Tensile stress
B. Compressive stress
C. Shear stress
D. None of these
Answer: C
457. The ratio of circumferential stress to longitudinal stress in a thin cylinder subjected to an internal pressure is
A. 1/2
B. 1
C. 2
D. 4
Answer: C
458. For a shoe brake, the equivalent coefficient of friction is equal to (where μ = Actual coefficient of friction, and θ = Semi-block angle)
A. 2μ sinθ/(θ + sinθ)
B. μ sinθ/(2θ + sin 2θ)
C. 4μ sinθ/(θ + sinθ)
D. 4μ sinθ/(2θ + sin 2θ)
Answer: D
459. When a hole of diameter ‘d’ is punched in a metal of thickness ‘t’, then the force required to punch a hole is equal to (where τu = Ultimate shear strength of the material of the plate)
A. d.t.τu
B. πd.t.τu
C. π/4 × d².τu
D. π/4 × d² × tτu
Answer: B
460. In static loading, stress concentration is more serious in
A. Brittle materials
B. Ductile materials
C. Brittle as well as ductile materials
D. Elastic materials
Answer: A
461. Which of the following statement is correct, for two shafts connected in parallel?
A. Torque in each shaft is the same
B. Shear stress in each shaft is the same
C. Angle of twist of each shaft is the same
D. Torsional stiffness of each shaft is the same
Answer: C
462. According to I.B.R., the efficiency of a double riveted butt joint with double cover straps of equal width should be
A. 45 to 60%
B. 63 to 70%
C. 70 to 83%
D. 80 to 90%
Answer: C
463. The velocity of sliding __________ the distance of the point of contact from the pitch point.
A. Is directly proportional to
B. Is inversely proportional to
C. Is equal to cos φ multiplied by
D. Does not depend upon
Answer: A
464. 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
465. The period during which the cam follower remains at rest, when cam moves, is known as
A. Constant period
B. Fixed period
C. Dwell period
D. Idle period
Answer: C
466. According to I.B.R., the efficiency of a triple riveted butt joint with double straps of unequal width (5 rivets per pitch length) should be
A. 45 to 60%
B. 63 to 70%
C. 70 to 83%
D. 80 to 90%
Answer: D
467. Crowning on pulley helps
A. In decreasing the slip of the belt
B. In increasing the slip of the belt
C. To keep the belt in centre on a pulley while it is in motion
D. To increase pulley life
Answer: C
468. Which of the following coupling is used to connect two shafts which have both lateral and angular misalignment?
A. Bushed pin type coupling
B. Universal coupling
C. Oldham coupling
D. All of these
Answer: D
469. An imaginary circle which by pure rolling action gives the same motion as the actual gear, is called
A. Addendum circle
B. Dedendum circle
C. Pitch circle
D. Clearance circle
Answer: C
470. Which of the following statement is wrong for a connecting rod?
A. The connecting rod will be equally strong in buckling about X-axis and Y-axis, if Ixx = 4 Iyy
B. If Ixx > 4 Iyy, the buckling will occur about Y-axis
C. If Ixx < 4 Iyy, the buckling will occur about X-axis
D. The most suitable section for the connecting rod is T-section
Answer: D
471. 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. Both A. and B.
Answer: D
472. Which of the following statement is wrong?
A. A key is used as a temporary fastening
B. A key is subjected to tensile stresses
C. A key is always inserted parallel to the axis of the shaft
D. A key prevents relative motion between the shaft and boss of the pulley
Answer: B
473. A spring is used to
A. Measure forces
B. Apply forces
C. Store energy
D. All of these
Answer: D
474. The stiffness of a closely coiled helical spring subjected to an axial load W is equal to (where G = Modulus of rigidity, and n = Number of active coils)
A. Gd⁴/ 8D3n
B. Gd3/ 8D3n
C. Gd⁴/ 4D3n
D. Gd⁴/ 8D²n
Answer: A
475. Two helical springs of the same material and of equal circular cross-section, length and number of turns, but having radii 80 mm and 40 mm, kept concentrically (smaller 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
476. When the fulcrum is in between the load and effort, the lever is said to be of
A. First type
B. Second type
C. Third type
D. Any one of these
Answer: A
477. A column is known as a long column if the slenderness ratio is
A. 40
B. 50
C. 70
D. 100
Answer: D
478. 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
479. The yield point in static loading is __________ as compared to fatigue loading.
A. Higher
B. Lower
C. Same
D. None of these
Answer: A
480. 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
481. The velocity factor for ordinary cut gears operating at velocities up to 12.5 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: B
482. The bearings of medium series have capacity __________ over the light series.
A. 10 to 20%
B. 20 to 30%
C. 30 to 40%
D. 40 to 50%
Answer: C
483. The square threads are usually found on
A. Spindles of bench vices
B. Railway carriage couplings
C. Feed mechanism of machine tools
D. Screw cutting lathes
Answer: C
484. Multiple threads are used to secure
A. Low efficiency
B. High efficiency
C. High load lifting capacity
D. High mechanical advantage
Answer: B
485. 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 shafting are equally strong
D. The shafts are not made by rolling process
Answer: A
486. 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
487. The permissible stress in the fillet weld is 100 N/mm². The fillet weld has equal leg lengths of 15 mm each. The allowable shearing load on the weldment per cm length of the weld is
A. 7.5 kN
B. 10.6 kN
C. 15 kN
D. 22.5 kN
Answer: B
488. The smallest diameter of an external or internal screw thread is known as
A. Minor diameter
B. Major diameter
C. Pitch diameter
D. None of these
Answer: A
489. 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
490. The piston pin bearings in heavy duty diesel engines are
A. Needle roller bearings
B. Tapered roller bearings
C. Spherical roller bearings
D. Cylindrical roller bearings
Answer: A
491. The tension on the slack side of the belt is __________ the tension on the tight side of the belt.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer: B
492. In skew bevel gearing, the axes of shafts are
A. Intersecting and the teeth are curved
B. Non-intersecting and nonparallel and the teeth are curved
C. Non-intersecting and non-parallel and the teeth are straight
D. None of the above
Answer: C
493. The ball bearings are provided with a cage
A. To reduce friction
B. To facilitate slipping of balls
C. To prevent the lubricant from flowing out
D. To maintain the balls at a fixed distance apart
Answer: D
494. A single strap butt joint is always in __________ shear.
A. Single
B. Double
C. Triple share
D. None of these
Answer: A
495. The cam follower extensively used in aircraft engines is
A. Knife edge follower
B. Flat faced follower
C. Spherical faced follower
D. Roller follower
Answer: D
496. The shear stress in a beam varies from zero at the outer fibers to a maximum at the________.
A. Neutral surface
B. Upper surface
C. Lower surface
D. None of these
Answer: A
497. In helical gears, the distance parallel to the axis, between similar faces of adjacent teeth, is called
A. Normal pitch
B. Axial pitch
C. Diametral pitch
D. Module
Answer: B
498. The velocity factor for precision metallic gears cut with high accuracy and operating at velocities up to 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
499. In case of pressure vessels having open ends, the fluid pressure induces
A. Longitudinal stress
B. Circumferential stress
C. Shear stress
D. None of these
Answer: B
500. When the bolt is very yielding as compared to the connected members, then the resultant load on the bolt will be equal to the
A. Initial tension
B. External load applied
C. Sum of the initial tension and external load applied
D. Initial tension or external load, whichever is greater
Answer: D
501. 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
501. Factor of safety for fatigue loading is the ratio of
A. Elastic limit to the working stress
B. Elastic limit to the yield point
C. Endurance limit to the working stress
D. Young’s modulus to the ultimate tensile strength
Answer: C
502. If T is the actual number of teeth on a helical gear and φ is the helix angle for the teeth, then formative number of teeth is written as
A. T sec3φ
B. T sec²φ
C. T/sec3φ
D. T cosecφ
Answer: A
503. The stress which vary from a minimum value to a maximum value of the same nature (i.e. tensile or compressive) is called
A. Repeated stress
B. Yield stress
C. Fluctuating stress
D. Alternating stress
Answer: C
504. A screw is said to be a self locking screw, if its efficiency is
A. Less than 50%
B. More than 50%
C. Equal to 50%
D. None of these
Answer: Option
505. In designing a key, it is assumed that the distribution of forces along the length of key
A. Varies linearly
B. Is uniform throughout
C. Varies exponentially, being more at the torque-input end
D. Varies exponentially, being less at the torque-input end
Answer: B
506. The design of the pressure vessel is based on
A. Longitudinal stress
B. Hoop stress
C. Longitudinal and hoop stress
D. None of these
Answer: B
507. A triple riveted butt joint with double straps of unequal width is to be designed for a boiler shell. The pitch of the rivets in the outer row is double the pitch in the inner row and zigzag riveting is proposed. Which of the following statement is correct?
A. There are four rivets per pitch length, all in double shear
B. There are four rivets per pitch length, out of which two are in single shear and two are in double shear
C. There are five rivets per pitch length, all in double shear
D. There are five rivets per pitch length, out of which four are in double shear and one is in single shear
Answer: D
508. A chain drive transmits __________ power as compared to belt drive.
A. More
B. Less
C. Same
D. None of these
Answer: A
510. For maximum power, the velocity of the belt will be
A. √(T/m)
B. √(T/2m)
C. √(T/3m)
D. None of these
Answer: C
511. The expression 0.175 – 0.841/T is the Lewis form factor for
A. 14½° composite and full depth involute system
B. 20° full depth involute system
C. 20° stub system
D. None of the above
Answer: C
512. The design of pin of a rocker arm of an I.C. engine is based on
A. Bearing failure
B. Shearing failure
C. Bending failure
D. All of these
Answer: D
513. 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
514. A thin spherical shell of internal diameter d is subjected to an internal pressure p. If V is the storage capacity of shell, then its diameter will be
A. (6V/ π)1/2
B. (6V/ π)1/3
C. (6V/ π)2
D. (6V/ π)3
Answer: B
515. 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
516. The draw of cotter should not be more than
A. 3 mm
B. 6 mm
C. 8 mm
D. 12 mm
Answer: A
517. The temperature at which the new grains are formed in the metal is known as
A. Lower critical temperature
B. Upper critical temperature
C. Recrystallization temperature
D. None of these
Answer: C
518. The taper on key is given on
A. Bottom side only
B. Top side only
C. On both sides
D. Any side
Answer: B
519. 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
520. 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)⁴
D. Inversely proportional to (shaft diameter)⁴
Answer: D
521. 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
522. The resultant axial load on a bolt depends upon
A. External load applied
B. Initial tension due to tightening of the bolt
C. Relative elastic yielding of the bolt and the connected members
D. All of the above
Answer: D
523. The buckling load will be maximum for a column, if
A. One end of the column is clamped and the other end is free
B. Both ends of the column are clamped
C. Both ends of the column are hinged
D. One end of the column is hinged and the other end is free
Answer: B
524. A flanged pipe joint will be a leak-proof joint, if the circumferential pitch of the bolts is (where d = Diameter of bolt hole)
A. Less than 20d
B. Greater than 30d
C. Between 20d and 30d
D. Equal to inside diameter of pipe
Answer: C
525. Which of the following is an anti-friction bearing?
A. Journal bearing
B. Pedestal bearing
C. Collar bearing
D. Needle bearing
Answer: D
526. For low and moderate speed engines, the cam follower should move with
A. Uniform velocity
B. Simple harmonic motion
C. Uniform acceleration and retardation
D. Cycloidal motion
Answer: B
527. The diameter of the rivet hole is usually __________ the nominal diameter of the rivet.
A. Equal to
B. Less than
C. More than
D. None of these
Answer: C
528. When a machine member is subjected to torsion, the torsional shear stress set up in the member is
A. Zero at both the centroidal axis and outer surface of the member
B. Maximum at both the centroidal axis and outer surface of the member
C. Zero at the centroidal axis and maximum at the outer surface of the member
D. Maximum at the centroidal axis and zero at the outer surface of the member
Answer: B
529. The root angle of a bevel gear is equal to
A. Pitch angle – addendum angle
B. Pitch angle + addendum angle
C. Pitch angle – dedendum angle
D. Pitch angle + dedendum angle
Answer: C
530. Which of the following statement is wrong?
A. The solid length of a spring is the product of total number of coils and the diameter of the wire
B. The spring index is the ratio of mean diameter of the coil to the diameter of the wire
C. The spring stiffness is the load required per unit deflection of the spring
D. The pitch of the coil is the axial distance between adjacent coils in the compressed state
Answer: D
531. Which of the following bearing is preferred for oscillating conditions?
A. Double row roller bearing
B. Taper roller bearing
C. Angular contact single row ball bearing
D. Needle roller bearing
Answer: D
532. The usual proportion for the width of key is (where d = Diameter of shaft or diameter of hole in the hub)
A. d/8
B. d/6
C. d/4
D. d/2
Answer: C
533. A hollow shaft will transmit a __________ torque than a solid shaft of the same mass and same material.
A. Smaller
B. Greater
C. Medium
D. None of these
Answer: B
534. The groove angle of the pulley for rope drive is usually
A. 20°
B. 35°
C. 45°
D. 60°
Answer: C
535. The diameter of knuckle pin in a knuckle joint is usually taken as (where d = Diameter of the rod)
A. 0.5 d
B. 0.8 d
C. d
D. 1.2 d
Answer: C
536. The centrifugal tension in the belt
A. Increases the power transmitted
B. Decreases the power transmitted
C. Has no effect on the power transmitted
D. Is equal to maximum tension on the belt
Answer: C
537. A woodruff key is
A. A tapered key with head at one end
B. Fitted in pairs at right angles
C. Capable of tilting in a recess milled out in the shaft
D. All of the above
Answer: C
538. The wear load should be __________ the dynamic load.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer: B
539. The power transmitted by means of a belt depends upon
A. Velocity of the belt
B. Tension under which the belt is placed on the pulleys
C. Arc of contact between the belt and the smaller pulley
D. All of the above
Answer: D
540. According to Indian standard specifications, plain carbon steel designated by 40C8 contains carbon
A. 0.20 to 0.40%
B. 0.35 to 0.45%
C. 0.40 to 0.60%
D. None of these
Answer: B
541. The longitudinal joint in boilers is used to get the required
A. Length of boiler
B. Diameter of boiler
C. Length and diameter of boiler
D. Efficiency of boiler
Answer: B
542. A riveted joint is a __________ fastening.
A. Permanent
B. Temporary
C. Either A or B
D. None of these
Answer: A
543. A long helical spring having a spring stiffness of 12 kN/m and number of turns 20, breaks into two parts with number of turns 10 each in both the parts. If the two parts are connected in series, then the softness of the resultant spring will be
A. 6 kN/m
B. 12 kN/m
C. 24 kN/m
D. 30 kN/m
Answer: B
544. A locking device extensively used in automobile industry is a
A. Jam nut
B. Castle nut
C. Sawn nut
D. Ring nut
Answer: B
545. Failure of a material is called fatigue when it fails
A. At the elastic limit
B. Below the elastic limit
C. At the yield point
D. Below the yield point
Answer: D
546. The endurance limit for a mirror polished material will be __________ as compared to unpolished material.
A. Same
B. Less
C. More
D. None of these
Answer: C
548. The V-belts are particularly suitable for __________ drives.
A. Short
B. Long
C. Both A and B
D. None of these
Answer: A
549. A pressure vessel is said to be a thick shell, if the ratio of wall thickness to its diameter is
A. Equal to 1/10
B. Less than 1/10
C. Greater than 1/10
D. None of these
Answer: C
550. The lead angle of a worm is 22.5°. Its helix angle will be
A. 22.5°
B. 45°
C. 67.5°
D. 90°
Answer: C
551. The ends of the leaves of a semi-elliptical leaf spring are made triangular in order to
A. Obtain variable moment of inertia (I) in each leaf
B. Permit each leaf to act as an overhanging beam
C. Have variable bending moment (M) in each leaf
D. Make M/I constant throughout the length of the leaf
Answer: D
552. When a load W is applied suddenly on a bar of cross-sectional area A, the stress induced in the bar will be
A. W/A
B. W/2A
C. 2W/A
D. 3W/A
Answer: C
554. When the material of key and shaft is same, and the width of key is one-fourth of the diameter of shaft D., then length of key will be
A. 0.8 d
B. 1.2 d
C. 1.57 d
D. 1.8 d
Answer: C
555. A compound belt 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. None of the above
Answer: D
556. The application of second type levers is found in
A. Handle of a hand pump
B. Hand wheel of a punching press
C. Lever of a loaded safety valve
D. A pair of tongs
Answer: C
557. When a shaft is subjected to combined twisting moment (T) and bending moment (M), then the equivalent twisting moment is equal to
A. (1/2) × √(M² + T²)
B. √(M² + T²)
C. (1/2) × [M + √(M² + T²)]
D. M + √(M² + T²)
Answer: B
558. For crank shaft bearings, the ratio of the length of the journal to its diameter is_________.
A. Less than unity
B. Greater than unity
C. Equal to 1
D. None of these
Answer: A
559. Pitch point of a cam is
A. A point on the pitch curve having minimum pressure angle
B. A point on the pitch curve having maximum pressure angle
C. Any point on the pitch curve
D. Any point on the pitch circle
Answer: B
560. The property of a bearing material which has the ability to accommodate small particles of dust, grit etc. without scoring the material of the journal, is called
A. Bondability
B. Embeddability
C. Comformability
D. Fatigue strength
Answer: B
561. The face angle of a bevel gear is equal to
A. Pitch angle – addendum angle
B. Pitch angle + addendum angle
C. Pitch angle – dedendum angle
D. Pitch angle + dedendum angle
Answer: B
562. A thin spherical shell of internal diameter d is subjected to an internal pressure p. If σt is the tensile stress for the shell material, then thickness of shell is equal to
A. pd/σt
B. pd/2σt
C. pd/3σt
D. pd/4σt
Answer: D
563. When the pulley or other mating piece is required to slide along the shaft, a __________ sunk key is used.
A. Rectangular
B. Square
C. Parallel
D. None of these
Answer: C
564. The algebraic difference between the maximum limit and the basic size is called
A. Lower deviation
B. Upper deviation
C. Actual deviation
D. Mean deviation
Answer: B
565. If b denotes the face width and L denotes the cone distance for a bevel gear, then the bevel factor is written as
A. b/L
B. b/2L
C. 1 – 2 b.L
D. 1 – (b/L)
Answer: D
567. In order to have smooth operation, the minimum number of teeth on the smaller sprocket, for moderate speeds, should be
A. 15
B. 17
C. 21
D. 25
Answer: B
568. The included angle for the British standard whitworth thread is
A. 29°
B. 47.5°
C. 55°
D. 60°
Answer: C
569. The metal suitable for bearings subjected to light loads is
A. Silicon bronze
B. White metal
C. Monel metal
D. Phosphor bronze
Answer: D
570. In order to withstand resistance to wear, the best profile of gear is
A. 14½° full depth involute tooth
B. 20° full depth involute tooth
C. 20° involute stub tooth
D. 14½° stub tooth
Answer: A
571. In a steam engine, the valve rod is connected to an eccentric rod by means of
A. Cotter joint
B. Knuckle joint
C. Universal joint
D. Flange coupling
Answer: B
572. Guest’s theory is used for
A. Brittle materials
B. Ductile materials
C. Elastic materials
D. Plastic materials
Answer: B
573. Which of the following property is desirable in parts subjected to shock and impact loads?
A. Strength
B. Stiffness
C. Brittleness
D. Toughness
Answer: D
574. The steel widely used for motor car crankshafts is
A. Nickel steel
B. Chrome steel
C. Nickel Chrome steel
D. High speed steel
Answer: B
575. According to I.B.R., the thickness of the boiler shell should not be less than
A. 4 mm
B. 5 mm
C. 6 mm
D. 7 mm
Answer: D
576. Gears are casted by
A. Sand mould casting
B. Slush casting
C. Permanent mould casting
D. Centrifugal casting
Answer: C
577. A tapered key which fits in a key way in the hub and is flat on the shaft, is known as
A. Feather key
B. Gib-head key
C. Wood ruff key
D. Flat saddle key
Answer: D
578. When a bolt is subjected to an external load, the stress induced in the bolt will be
A. Tensile stress
B. Shear stress
C. Combined tensile and shear stress
D. Any one of these
Answer: D
579. The rocker arms in internal combustion engines are of__________.
A. First type levers
B. Second type levers
C. Third type levers
D. None of these
Answer: A
580. Which one of the following loading is considered for the design of axles?
A. Bending moment only
B. Twisting moment only
C. Combined bending moment and twisting moments
D. Combined action of bending moment, twisting moment and axial thrust
Answer: A
581. When a metal or alloy is cold worked,
A. Its hardness and strength increases
B. It is worked below recrystallization temperature
C. Both A. and B.
D. None of these
Answer: C
582. In designing a sleeve coupling, outer diameter of the sleeve is taken as (where d = Diameter of the shaft)
A. d + 17 mm
B. 2d + 13 mm
C. 2d + 20 mm
D. 3.5d
Answer: B
583. When the shaft rotates in anticlockwise direction at high speed in a bearing, it will
A. Have contact at the bottom most of the bearing
B. Move towards right of the bearing making metal to metal contact
C. Move towards right of the bearing making no metal to metal contact
D. Move towards left of the bearing making metal to metal contact
Answer: C
584. A cotter joint is used to connect two __________ rods.
A. Co-axial
B. Perpendicular
C. Parallel
D. None of these
Answer: A
585. The difference between the upper limit and lower limit of a dimension is called
A. Nominal size
B. Basic size
C. Actual size
D. Tolerance
Answer: D
586. The stress in the bar when the load is applied suddenly is __________ as compared to the stress induced due to gradually applied loads.
A. Same
B. Double
C. Three times
D. Four times
Answer: B
587. All stresses produced in a belt are
A. Compressive stresses
B. Tensile stresses
C. Both tensile and compressive stresses
D. Shear stresses
Answer: B
588. A screw is specified by its
A. Major diameter
B. Minor diameter
C. Pitch diameter
D. Pitch
Answer: A
589. The longitudinal stress is __________ of the circumferential stress.
A. One-half
B. Two-third
C. Three-fourth
D. Double
Answer: A
590. A rivet is specified by
A. Shank diameter
B. Length of rivet
C. Type of head
D. Length of tail
Answer: A
591. A shaft is subjected to
A. Bending stresses
B. Shear stresses
C. Combined bending and shear stresses
D. All of these
Answer: D
592. When a bolt and nut is made of mild steel, then the effective height of nut is made equal to (where d = Nominal diameter of bolt)
A. 0.5 d
B. 0.75 d
C. d
D. 1.25 d
Answer: C
593. A closely coiled helical spring is acted upon by an axial force. The maximum shear stress developed in the spring is τ. The half of the length of the spring if cut off and the remaining spring is acted upon by the same axial force. The maximum shear stress in the spring in new condition will be
A. τ/2
B. τ
C. 2 τ
D. 4 τ
Answer: B
594. The radial distance from the __________ to the clearance circle is called working depth.
A. Addendum circle
B. Dedendum circle
C. Pitch circle
D. None of these
Answer: A
595. A screw will be self locking, if
A. Friction angle is less than helix angle
B. Friction angle is more than helix angle
C. Friction angle is equal to helix angle
D. Efficiency of screw is 100%
Answer: B
596. In cyclic loading, stress concentration is more serious in
A. Brittle materials
B. Ductile materials
C. Brittle as well as ductile materials
D. Elastic materials
Answer: B
597. In a turnbuckle, if one of the rods has left hand threads, then the other rod will have
A. Right hand threads
B. Left hand threads
C. Multiple threads
D. Pointed threads
Answer: A
598. The railway carriage couplings have
A. Square threads
B. Acme threads
C. Knuckle threads
D. Buttress threads
Answer: D
599. The anti-friction bearings
A. Have low starting and low running friction at moderate speeds
B. Have high initial cost
C. Can carry both radial and thrust loads
D. All of these
Answer: D
600. Lewis equation is applied
A. Only to the pinion
B. Only to the gear
C. To stronger of the pinion or gear
D. To weaker of the pinion or gear
Answer: D
601. The bearing characteristic number in a hydrodynamic bearing depends upon
A. Length, width and load
B. Length, width and speed
C. Viscosity, speed and load
D. Viscosity, speed and bearing pressure
Answer: D
602. Which of the following welded joint is designed for shear strength?
A. Transverse fillet welded joint
B. Parallel fillet welded joint
C. Butt welded joint
D. All of these
Answer: B
603. The surface finish factor for a mirror polished material is
A. 0.45
B. 0.65
C. 0.85
D. 1
Answer: D
604. According to maximum normal stress theory, the maximum normal stress in the shaft is
A. (1/2) × √(σ² × 4τ²)
B. √(σ² × 4τ²)
C. (1/2) × [σ + √(σ² × 4τ²)]
D. σ + √(σ² × 4τ²)
Answer: D
605. The dynamic tooth load is due to
A. Inaccuracies of tooth spacing
B. Irregularities in tooth profiles
C. Deflections of teeth under load
D. All of these
Answer: D
606. In helical bevel gearing, the axes of shafts are __________ and the teeth are curved.
A. Intersecting
B. Non-intersecting and non-parallel
C. Intersecting and non-parallel
D. None of these
Answer: B
607. In a flange coupling, the keys are staggered at __________ along the circumference of the shafts in order to divide the weakening effect caused by key ways.
A. 90°
B. 135°
C. 160°
D. 180°
Answer: A
608. In the levers of __________ type, the mechanical advantage is less than one.
A. First
B. Second
C. Third
D. None of these
Answer: C
609. The strength of the unriveted plate (P) per pitch length is equal to
A. p.d.σt
B. p.t.σt
C. (p – d) σt
D. (p – d) t.σt
Answer: B
610. A shaft coupling should
A. Be easy to connect or disconnect
B. Transmit full power of the shaft
C. Hold the shafts in perfect alignment
D. All of these
Answer: D
611. The function of the washer is to
A. Fill up the axial gap
B. Provide bearing area
C. Provide cushioning effect
D. Absorb shocks and vibrations
Answer: D
612. Shaft coupling is used in machinery to
A. Introduce mechanical flexibility
B. Introduce protection against over loads
C. Reduce the transmission of shock loads
D. All of these
Answer: D
613. A saddle key __________ power through frictional resistance only.
A. Transmits
B. Does not transmit
C. Either A or B
D. None of these
Answer: A
614. The cam follower generally used in automobile engines is
A. Knife edge follower
B. Flat faced follower
C. Spherical faced follower
D. Roller follower
Answer: C
615. The shear modulus of resilience is proportional to
A. Shear stress
B. (Shear stress)²
C. (Shear stress)3
D. (Shear stress)⁴
Answer: B