Machine Design Set 21

Mechanical Engineering

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This set of Machine Design Multiple Choice Questions & Answers (MCQs) focuses on Machine Design Set 21

Q1 | The resilience of a bolt may be increased by
  • Increasing the diameter of threaded portion
  • Providing an under cut
  • Increasing shank diameter
  • Increasing the size of head
  • Increasing its length
Answer: Increasing its length
Q2 | A key and a shaft are made from the same material. The key is rectangular with a width of D/4 and a height of 3D/16. The shaft is under torsion only. The necessary length of the key for equal strength of the shaft and key will be
  • 1.25 D
  • D
  • 1.57 D
  • 1.73 D
  • 2.00 D
Answer: 1.57 D
Q3 | Monel metal is
  • Copper-nickel alloy
  • Nickel-chromium alloy
  • Aluminium-copper alloy
  • Aluminium-silver alloy
  • Chromium-molybdenum alloy
Answer: Copper-nickel alloy
Q4 | The cam follower generally used in automobiles is
  • Mushroom type
  • Flat type
  • Spherical type
  • Roller type
  • Knife edge type
Answer: Mushroom type
Q5 | The value of Young's modulus of elasticity in ascending order for glass, lead, phosphor bronze, steel and wood is
  • Wood, glass, lead, phosphor bronze, steel
  • Wood, glass, phosphor bronze, lead steel
  • Wood, phosphor bronze, lead glass steel
  • Wood, lead, glass, phosphor bronze, steel
  • Wood, phosphor bronze, glass, lead, steel
Answer: Wood, lead, glass, phosphor bronze, steel
Q6 | Taper roller bearings are used in automobiles for
  • Differential
  • Engine crankshaft
  • Gear box
  • Small end of connecting rod
  • Wheels
Answer: Wheels
Q7 | In hydrodynamic bearings
  • The oil film pressure is generated by external pump
  • The oil film pressure is generated by dead weight of shaft
  • The oil film pressure is generated only when the shaft rotates
  • The oil film is sufficiently thick
  • None of the above
Answer: The oil film pressure is generated only when the shaft rotates
Q8 | Dibasic acid esters have
  • fast evaporation at low temperatures
  • do not wet the metal surface
  • low film strength
  • Increasing the diameter of threaded portion
  • horizontal viscosity-temperature curves
Answer: horizontal viscosity-temperature curves
Q9 | The turbular section of a column has
  • Increasing the diameter of threaded portion
  • low buckling strength
  • negligible buckling strength
  • high buckling strength
Answer: high buckling strength
Q10 | The shape factor of standard rolled beam section varies in the range
  • Increasing the diameter of threaded portion
  • 1.0 to 1.1
  • 1.2 to 1.3
  • 1.1 to 1.2
  • 1.3 to 1.4
Answer: 1.1 to 1.2
Q11 | For maximum horse power transmission in belt drives the velocity of belt left such that the ration tight side driving tension/centrifugal tension is
  • 1
  • 2
  • 3
  • 4
  • None of the above
Answer: 2
Q12 | The ratio of the strength of the weld mterial to that of the parent body is
  • Increasing the diameter of threaded portion
  • more than one
  • less than one
  • equal to one
Answer: more than one
Q13 | Hot isostatic pressing of metals reduces
  • porosity
  • Increasing the diameter of threaded portion
  • endurance limit
  • fatigue strength
  • ductility
Answer: porosity
Q14 | With a punch for which the maximum crushing stress is 4 times the maximum shearing stress of the plate, the biggest hole that can be punched in the plate would be of diameter equal to
  • 4 x plate thickness
  • 1/4 x thickness of plate
  • 1/2 x thickness of plate
  • 2 x plate thickness
  • Plate thickness
Answer: Plate thickness
Q15 | Power capacitors are used
  • To improve electrical capacity
  • To improve efficiency
  • To reduce power factor
  • To improve power factor
  • None of the above
Answer: To improve power factor
Q16 | The ratio of the area of cross-section of a circular section and the area of its core is
  • 10
  • Increasing the diameter of threaded portion
  • 16
  • 12
  • 8
Answer: 16
Q17 | What type of gears are provided in a switch gear?
  • Spur gears
  • Helical gear
  • Bevel gears
  • Herringbone gears
  • None of the above
Answer: None of the above
Q18 | Allen bolts are
  • Self-screwing bolts
  • Self locking bolts
  • Counter sunk
  • Used on aircraft
  • Provided with hexagonal depression in head
Answer: Provided with hexagonal depression in head
Q19 | Centrifugal tension in belts
  • reduces power transmission
  • increases power transmission
  • does not affect power transmission
  • none of the above
  • Cast steel
Answer: reduces power transmission
Q20 | The stress concentration factor for flat bar in tension with a circular hole, is
  • 1.5
  • 1
  • 2.5
  • 1.25
  • 2
Answer: 2.5
Q21 | Which of the following statement about wire ropes is not correct?
  • Wire ropes are used as guy wires with the steel towers
  • Wire ropes have the disadvantage of rigidity and poor strength
  • Increasing the diameter of threaded portion
  • Wire ropes require special fittings for proper end connections
  • Wire ropes are given initial tension
Answer: Wire ropes have the disadvantage of rigidity and poor strength
Q22 | The blow off pressure of a safety valve is
  • Slightly above atmospheric pressure
  • Half of the boiler working pressure
  • 2 x boiler working pressure
  • Boiler working pressure
  • 106% of boiler working pressure
Answer: 106% of boiler working pressure
Q23 | As viscosity of lubricating oil decreases, bearing load capacity
  • increases linearly
  • decreases
  • Increasing the diameter of threaded portion
  • increases exponentially
Answer: decreases
Q24 | The maximum strain at the end of plastic range of structural steel is about
  • 1.5 percent
  • 15.0 percent
  • Increasing the diameter of threaded portion
  • 11.0 percent
  • 0.11 percent
Answer: 1.5 percent
Q25 | The plastic design of a steel structure based on which of the following unsafe?
  • Kinematic method of plastic analyis
  • Mechanism method of plastic analysis
  • Upper bound theorem
  • All of the above
  • Increasing the diameter of threaded portion
Answer: All of the above
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