Design of Machine Elements 7

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Design of Machine Elements 7

Part 1: List for questions and answers of Design of Machine Elements –II

Q1.What is the load stress factor for cast iron gear pair if BHN = 300?
a) 1.89 N/mm^2
b) 1.62 N/mm^2
c) 1.44 N/mm^2
d) 1.413 N/mm^2

Q2.What is the deformation or dynamic factor if sum of errors on meshing teeth of steel pinion and gear is 32 x 10^-3 mm?
a) 284.8 N/mm
b) 300.23 N/mm
c) 320.5 N/mm
d) 368 N/mm

Q3.Which of the following gear tooth failures is/are induced when maximum Hertz contact stress on gear tooth surface exceeds surface endurance strength of tooth?
a) Abrasive strength
b) Corrosive wear
c) Destructive pitting
d) Galling

Q4.What is Scuffing?
a) Lubrication failure
b) Surface fatigue failure
c) Surface injury on matting teeth surfaces
d) Wear due to chemical action by lubricants

Q5. If (σb x Y)pinion > ( σb x Y)gear then ________ is designed for bending.
a) Pinion
b) Gear
c) Both a. And b.
d) None of the above

Q6. In force analysis of spur gears which component of force assists the rotation on driven gear?
a) Axial component
b) Radial component
c) Tangential component
d) All of the above

Q7.What is the advantages of smaller pressure angles?
a) High radial force
b) High separating force
c) High contact ratio
d) All of the above

Q8.In which of the following processes, tooth ends are made thinner?
a) Backlash effect
b) Crowing of gear tooth
c) Hunting of gear tooth
d) None of the above

Q9.Spiral gears are used only if the axes of two shafts are non-intersecting, non-parallel and__________
a) Perpendicular
b) Parallel
c) Non-perpendicular
d) None of the above

Q10.Which gear is used if the axes of two shafts are neither intersecting nor parallel?
a) Hypoid gears
b) Worm gears
c) Both a and b
d) None of the above

Q11. Calculate the number of teeth on wheel, when number of teeth on pinion and wheel are equal. Pressure angle is 25 deg.
a) 11
b) 12
c) 7
d) 9

Q12.What is meant by contact ratio in gears?
a) Ratio of length of arc of approach and circular pitch
b) Ratio of circular pitch and length of arc of contact
c) Ratio of length of arc of recess and circular pitch
d) Ratio of length of arc of contact and circular pitch

Q13. Calculate number of teeth on wheel to avoid interference, if wheel has addendum coefficient of one and velocity ratio 4. Pressure angle being 22 deg. And gear ratio of 2
a) 10
b) 24
c) 34
d) None of the above

Q14.In involute gears what is the effect of centre distance variation on velocity ratio?
a) Velocity ratio increases
b) Velocity ratio decreases
c) It has no effect on velocity ratio
d) None of the above

Q15.Interference in gear tooth profiles can be avoided by
a) Modifying tooth profile
b) Modifying centre distance between pinion and wheel
c) Both a. And b
d) None of the above

Q16.What is meant by interference?
a) Mating of conjugate profiles of a tooth
b) Mating of involutes profiles of a tooth
c) Mating of non-involutes profiles of a tooth
d) All of the above

Q17.Herring-bone gears are also known as
a) Hypoid gears
b) Helical gears
c) Spiral gears
d) None of the above

Q18.Which of the following statements is true for gear drive?
a) Gear drives can transmit very large power
b) Gear drives have low transmission efficiency
c) Gear drives require more space
d) All of the above

Q19.A helical gear has normal module of 6 mm. What is the transverse module if helix angle is 25 deg.?
a) 4.95 mm
b) 500 mm
c) 5.43 mm
d) 6.62 mm

Q20.Which of the following statements is/are true?
a) Helical gears have high contact ratio than spur gears
b) Axial thrust is created by helical gears on bearings
c) Crossed helical gears are used for power and motion transmission
d) All of the above

Part 1: List for questions and answers of Design of Machine Elements –II

Q1. Answer: a

Q2. Answer: d

Q3. Answer: c

Q4. Answer: a

Q5. Answer: b

Q6. Answer: c

Q7. Answer: c

Q8. Answer: b

Q9. Answer: c

Q10. Answer: c

Q11. Answer: d

Q12. Answer: d

Q13. Answer: b

Q14. Answer: c

Q15. Answer: c

Q16. Answer: c

Q17. Answer: b

Q18. Answer: a

Q19. Answer: d

Q20. Answer: d