Design Of Machine Elements Set 6

Mechanical Engineering

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This set of Design of Machine Elements Multiple Choice Questions & Answers (MCQs) focuses on Design Of Machine Elements Set 6

Q1 | Cylinder roller creates lesser noise than deep groove ball bearing.
  • true
  • false
Answer: false
Explaination:
due to line contact, cylinder roller creates far more noise.
Q2 | Straight bevel gears are easy to design and manufacture and give reasonably good service with quieter operation.
  • true
  • no, noise problem
  • no, vibration problem
  • none of the listed
Answer: no, noise problem
Explaination:
they produce a lot of noise while working.
Q3 | Which of the following creates smoother motion?
  • straight bevel gears
  • spiral bevel gears
  • equal for straight and spiral
  • none of the mentioned
Answer: spiral bevel gears
Explaination:
spiral bevel gear has smooth engagement which results in quieter operation.
Q4 | When the pitch angle is greater than 90⁰, it is called external bevel gear.
  • true
  • internal
  • helical
  • herringbone
Answer: internal
Explaination:
for external bevel gear, pitch angle is less than 90⁰.
Q5 | If pitch angle is >90, the bevel gear is?
  • internal
  • external
  • crown
  • static
Answer: internal
Explaination:
nomenclature.
Q6 | Crown gears having a pitch angle of 90⁰
  • 90
  • <90
  • >90
  • none of the listed
Answer: >90
Explaination:
application of crown gear according to its structure.
Q7 | Which of the following are characteristics of skew bevel gears?
  • straight teeth
  • mounted on parallel shafts
  • mounted on intersecting shafts
  • all of the mentioned
Answer: straight teeth
Explaination:
they are used in non-parallel and non-intersecting shafts.
Q8 | Hypoid gears are based on surfaces that are paraboloids of revolution.
  • true
  • false
Answer: false
Explaination:
they are hyperboloids of revolution.
Q9 | When two hyperboloids are rotated, the resulting motion is
  • sliding
  • turning
  • combination of turning and sliding
  • rotary
Answer: combination of turning and sliding
Explaination:
there is turning as well as sliding motion.
Q10 | Zerol gears are straight bevel gears with zero spiral angle.
  • true
  • false
Answer: false
Explaination:
they happen to fall in the category of spiral bevel gears.
Q11 | Zerol gears give lesser contact ratio.
  • true
  • no, larger contact ratio
  • zero contact
  • none of the listed
Answer: no, larger contact ratio
Explaination:
zerol gears have more gradual contact and slighter larger contact ratio.
Q12 | Hydrodynamic lubrication takes place in region?
  • bc
  • cd
  • both bc and cd
  • none of the mentioned
Answer: cd
Explaination:
in cd thick film of lubrication has developed.
Q13 | Coefficient of friction is minimum at
  • it is same at each point
  • b
  • c
  • d
Answer: c
Explaination:
it is minimum at the transition zone.
Q14 | Bearing modulus is the bearing characteristic number at
  • b
  • c
  • d
  • none of the listed
Answer: c
Explaination:
bcn modulus is the the bcn number corresponding to the minimum coefficient of friction.
Q15 | If viscosity of the lubricant is very low than BCN will lie in the region
  • bc
  • point c
  • cd
  • can’t be determined
Answer: bc
Explaination:
due to low viscosity, lubricant will not separate the two surfaces resulting in partial contact.
Q16 | The fundamental equation for viscous flow is given by ∆pbhᵌ/6µl where symbols have their usual meanings.
  • 6 is to be replaced by 3
  • 6 is to be replaced by 12
  • 6 is to be replaced by 9
  • 6 is to be replaced by 15
Answer: 6 is to be replaced by 12
Explaination:
it is givenby ∆pbhᵌ/12µl.
Q17 | A single transverse weld is preferred over
  • true
  • false
Answer: false
Explaination:
a single transverse weld is not preferred because the edge of the plate which is not welded can warp out of shape.
Q18 | Transverse fillet weld can be designed using the same equations as of parallel fillet weld.
  • true
  • false
Answer: false
Explaination:
vice versa is true as strength of transverse fillet weld is greater than that of parallel fillet weld.
Q19 | Which of the following are functions of bearings?
  • ensure free rotation of shaft with minimum friction
  • holding shaft in a correct position
  • transmit the force of the shaft to the frame
  • all of the listed
Answer: all of the listed
Explaination:
bearings are used for all the above listed purposes.
Q20 | Which of the following is measure of stiffness?
  • modulus of elasticity
  • modulus of plasticity
  • resilience
  • toughness
Answer: modulus of elasticity
Explaination:
stiffness is the ability of material to resist deformation under external load. hence it is measured by modulus of elasticity.
Q21 | Which of the following facts are true for resilience?
  • ability of material to absorb energy when deformed elastically
  • ability to retain deformation under the application of load or after removal of load
  • ability of material to absorb energy when deformed plastically
  • none of the mentioned
Answer: ability of material to absorb energy when deformed elastically
Explaination:
toughness is ability to store energy till proportional limit during deformation and to release this energy when unloaded.
Q22 | Stressed parts are always kept in tension.
  • true
  • false
Answer: true
Q23 | Shot blasting process improves the endurance limit of the component.
  • true
  • false
Answer: true
Q24 | Which process allows controlling grain structure of the product?
  • casting
  • forging
  • none of the mentioned
  • die casting
Answer: forging
Q25 | While designing a forging, the profile is selected such that the fibrous lines are parallel to the tensile forces and perpendicular to shear forces.
  • true
  • false
Answer: true
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