Material Science 10

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Electrical Engineering MCQ Question Papers: Campus Placement

Subject: Material Science 10

Part 4: List for questions and answers of Material Science

 

Q1. The example of artificial fibre is

a) Rayon

b) Cotton

c) Flax

d) Silk

 

Q2. Which among the following is not an example of impregnants?

a) Mineral oil

b) Chlorinated diphenyl

c) Vegetable oils

d) None of these

 

Q3. For very small cavities, discharge inception voltage

a) Decreases as the cavity depth increases

b) Increases as the cavity depth increases

c) Remains unaffected as the cavity depth increases

d) None of these

 

Q4. The liquid dielectrics contain voids or cavities within the medium or at the boundaries between the dielectric and the electrodes. The electric field strength in the voids is

a) Lower than that across the dielectric

b) Higher than that across the dielectric

c) Equal to that across the dielectric

d) None of these

 

Q5. Treeing phenomenon is observed in

a) Capacitors

b) Cables

c) Insulators

d) Only (a) and (b)

 

Q6. The spreading of spark channels during tracking, in the form of the branches of a tree is called

a) Bunching

b) Treeing

c) sparking

d) none of these 

 

Q7.The thermal breakdown stresses are

a) Lower under ac conditions than under dc condition

b) Greater under ac condition than dc condition

c) Equal in both condition

d) None of these

 

Q8. Within dielectric, an electron starting from the cathode will drift towards the anode and during this motion

a) Gains energy from the field and loses during collision

b) Gains energy during both motion and collision

c) Loses energy during both motion and collision

d) Loses energy from the field and gains during collision

 

Q9. Intrinsic breakdown occurs in time of the order of

a) 10^-5 s

b) 10^5 s

c) 10^-8 s

d) 10^8 s

 

Q10. Which is having higher breakdown strength?

a) Solid dielectrics

b) Liquid dielectrics

c) Gases dielectrics

d) Equal in all

 

Q11. Dielectric strength in case of mica can be expected to be more than

a) 500 kV/mm

b) 1500 kV/mm

c) 2500 kV/mm

d) 3500 kV/mm

 

Q12. All of the following dielectric materials are preferred for high frequency applications EXCEPT

a) Polyethylene

b) Butyl rubber

c) Teflon

d) Polystyrene 

 

Q13. Polar dielectrics are normally used for

a) high frequencies

b) microwaves

c) dc and power frequencies

d) none of the above

 

Q14. Which of the following is a polar dielectric ?

a) Teflon

b) Quartz

c) Nylon

d) Polyethylene

 

Q15. Which of the following is a non-polar dielectric ?

a) Polystyrene

b) Phenolic plastics

c) Plasticized cellulose acetate

d) Castor oil

 

Q16. The impurity in liquid dielectric which has significant effect in reducing the breakdown strength, is

a) dust

b) dissolved gases

c) moisture

d) ionic impurities

 

Q17. The relationship between the breakdown voltage V and gap d is normally given as

a) d=kV^2

b) d=kV^3

c) V=kd

d) v=kdn

 

Q18. A good dielectric should have all the following properties EXCEPT

a) high mechanical strength

b) high resistance to thermal deterioration

c) high dielectric loss

d) freedom from gaseous inclusions 

 

Q19. The variety of paper used for insulation purpose is

a) blotting paper

b) rice paper

c) craft paper

d) mill-board

 

Q20. Which variety of mica is hard and brittle ?

a) Muscovite

b) Phlogopite

c) Fibiolite

d) Lipidolite

 

Part 4: List for questions and answers of Material Science

 

Q1. Answer :a

 

Q2. Answer :d

 

Q3. Answer :a

 

Q4. Answer :b

 

Q5. Answer :d

 

Q6. Answer :b

 

Q7. Answer :a

 

Q8. Answer :a

 

Q9. Answer :c

 

Q10. Answer :a

 

Q11. Answer :a

 

Q12. Answer :b

 

Q13. Answer :c

 

Q14. Answer :c

 

Q15. Answer :a

 

Q16. Answer :c

 

Q17. Answer :d

 

Q18. Answer :c

 

Q19. Answer :c

 

Q20. Answer :d