140 TOP Objective Machine Design Questions and Answers pdf

111.    Aircraft body is usually fabricated by
(a) welding 
(b) precasting
(c) rivetting 
(d) casting
(e) unconventional methods.
Ans: c

112.    If two springs are in parallel then their overall stiffness will be
(a) half 
(b) same
(c) double 
(d) unpredictable
(e) none of the above.
Ans: c

113.    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
(e)    none of the above.
Ans: a

114.    Antifriction bearings are
(a)    sleeve bearings
(b)    hydrodynamic bearings
(c)    thin lubricated bearings
(d)    ball and roller bearings
(e)    none of the above.
Ans: e

115.    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
(e) Zp/N.
Ans: a

116.    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
(e) 25 microns.
Ans: c

117.    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
(e)    none of the above.
Ans: b

118.    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
(e)    unpredictable.
Ans: a

119.    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
(e)    none of the above.
Ans: c

120.    In oiliness 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
(e)    none of the above.
Ans: c

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Tricky Machine Design Multiple choice Questions and Answers pdf

91.    Silver-based solder is used for
(a)    flaring
(b)    brazing
(c)    soft soldering
(d)    fusion welding
(e)    none of the above.'
Ans: b

92.    For tight leakage joints, following type of thread is best suited
(a) metric
(b) buttress
(c) square
(d) acme
(e) NPT (national pipe threads).
Ans: e

93.    In order to permit the thermal expansion/contraction of tubing, it should be
(a) crimped
(b) honed
(c) flared
(d) bent
(e) none of the above.
 Ans: d

94.    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
(e)    none of the above.
Ans: d

95.    The strap end of a connecting rod of steam engine is joined by
(a)    big of cotter joint
(b)    sleeve and cotter joint
(c)    spigot socket cotter joint
(d)    knuckle joint
(e)    universal coupling.
Ans: a

96.    A backing ring is used inside the pipe joint when making a
(a) butt weld    
(b) fillet weld
(c) sleeve weld
(d) socket weld
(e) tube weld.
Ans: a

97.    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
(e)    none of the above.
Ans: d

97.    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 fiber 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
(e)    none of the above.
Ans: d

98.    When a nut is tightened by plapjng a washer below it, the bolt will be subjected to following type of loads
(a) compression
(b) tension
(c) shear     
(d) combined loads
(e) all of the above.
 Ans: b

99.    Gear box is used
(a)    to produce torque
(b)    for speed reduction
(c)    to obtain variable speeds
(d)    to increase efficiency of system
(e)    to damp out vibrations.
Ans: c

100.    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
(e)    all of the above.
Ans: d

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Hiried Machine Design interview Questions and Answers pdf

61.    A self locking screw has
(a)    fine threads
(b)    coarse threads
(c)    coefficient of friction > tangent of load angle
(d)    hole for inserting split pin
(e)    two nuts for locking.
Ans: c

62.    The designation M 33 x 2 of a bolt means
(a)    metric threads of 33 nos 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
(e)    none of the above.
Ans: c

63.    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 be-tween two parts
(d)    similar to stud
(e)    none of the above.
Ans: b

64.    Rivets are generally specified by
(a)     thickness of plates to be riveted
(b)     length of rivet
(c)    diameter of head
(d)    nominal diameter
(e)    all of the above.
 Ans: d

65.    The edges of a boiler plate are beveled to an angle of
(a) 30° 
(b) 45°
(c) 60° 
(d) 80°
(e) 85°.
Ans: d

66.    Which of the following is a permanent fastening ?
(a) bolts 
(b) keys
(c) cotters 
(d) rivets
(e) screws.
Ans: d

67. 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
(e) 2 d.
Ans: c

68.    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
(e) 0.75.
Ans: b

69.    Transverse fillet welded joints are designed for
(a)    tensile strength
(b)    compressive strength
(c)    shear strength
(d)    bending strength
(e)    torsional strength.
Ans: a

70.    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 splitted and bent in reverse direction at other end
(e)    none of the above.
Ans: a

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Realtime Machine Design Multiple choice Questions and Answers pdf

31.    The fatigue limit of a material
(a)    is greatly decreased by poor surface conditions
(b)    remains same irrespective of surface conditions
(c)    depends mainly on core composition
(d)    is dependent upon yield strength of material
(e)    none of the above.
Ans: a

32.    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
(e)    none of the above.
Ans: a

33.    Yield point in fatigue loading as compared to static loading is
(a)    same
(b)    higher
(c)    lower
(d)     depends on other factors
(e)     none of the above.
Ans: c

34.    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
(e)    is always beneficial.
 Ans: c

35.    The building up of worn and uridersized 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
(e)    all of the above.
Ans: a

36.    In nitrided parts, the origins of the fatigue cracks will occur at
(a)    surface
(b)    just below the surface
(c)    within the core
(d)    could occur anywhere
(e)    none of the above.
Ans: e

37.    Which process will increase the fatigue duration of parts ?
(a)    finishing and polishing
(b)    shot-peening
(c)    decarburisation
(d)    electroplating
(e)    all of the above".
Ans: b

38.    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
(e)    none of the above.
Ans: b

39.    Resistance to fatigue of a material is measured by
(a)    Young's modulus
(b)    coefficient of elasticity
(c)    elastic limit
(d)    ultimate tensile strength
(e)     endurance limit.
Ans: e

40.    In most machine members, the damping capacity of the material should be
(a)    low
(b)    zero
(c)    high
(d)    could be anything
(e)    none of the above.
 Ans: c

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