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Insulating materials and their properties and applications - MCQs - Part 4





Objectives on Insulating materials and their properties and applications in part 4

This sets of mcq's contains questions on insulating materials, properties, their applications, Ceramics, Mica, Asbestos, Varnish in part 4..

Click here to read part 1 of insulatng materials..

Click here to read part 2 of insulatng materials..

Click here to read part 3 of insulatng materials..

SET 1 of Insulating materials and their properties and applications mcq's

1. Material that does not allow current under normal conditions is
A. an insulator
B. conductor
C. semiconductor
D. superconductor

Answer A

Marks 1
2. Glass is ……….material.
A. tough
B. brittle
C. ductile
D. none of these

Answer B

Marks 1

3. Plastic is……….
A. good conductor of electricity
B. good conductor of heat
C. bad conductor of electricity
D. none of these

Answer C

Marks 1

4. ……is employed for cable insulation.
A. Rubber
B. Polystyrene
C. PVC
D. Phenol formaldehyde

Answer C

Marks 1

5. Which one of the following materials has the maximum dielectric strength?
A. soft rubber
B. glass
C. porcelain
D. polystyrene

Answer A

Marks 1

6. An insulating material starts conducting when the
A. temperature is raised to very high level
B. voltage applied exceeds the breakdown voltage
C. either (A) or (B)
D. none of these

Answer B

Marks 1

7. Surface resistivity of insulating material is reduced in ……….atmosphere.
A. humid
B. smoky & dirty
C. both (A) & (B)
D. none of above

Answer C

Marks 1

8. An exposure of insulating material to any contamination, causes increase in …..
A. dielectric loss
B. dielectric constant
C. dielectric strength
D. insulation resistance

Answer A

Marks 1

9. The most important qualities which a good insulating material should posses are
A. large insulation resistance& high dielectric strength
B. less thermal expansion & low dielectric loss
C. good heat conductivity, high mechanical strength & high melting point
D. both (A) & (B)

Answer D

Marks 1

10. Electro-mechanical breakdown of solid insulating materials occurs, due to
A. magnetic hum
B. vibrations
C. mechanical stresses produced by the electrical field
D. electrical stresses produced by the voltage fluctuations

Answer C

Marks 1

SET 2 of Insulating materials and their properties and applications mcq's

11. The materials which are used for storing electrical energy are classified as ……… materials.
A. insulating
B. dielectrics
C. superconducting
D. semiconducting

Answer B

Marks 1

12. Dielectrics have ……..free electrons.
A. a few
B. many
C. no
D. none of these

Answer C

Marks 1

13. Dielectric strength of gaseous dielectrics are depend on
A. polarity of electrodes
B. pressure & uniformly applied electric field
C. frequency of applied
D. all of above

Answer D

Marks 1

14. The dielectric breakdown strength of material depends on its …
A. composition
B. thickness
C. moisture content
D. all of the above

Answer D

Marks 1

15. Which of the following material is used for cable insulation ?
A. phenol formaldehyde
B. polytetra fluroethylene
C. polyvinyl chloride
D. acrylontrile butadiene styrene

Answer C

Marks 1

16. Bakelite is
A. a semi-conductor
B. incombustible
C. low resistance conductor
D. highly inflammable

Answer B

Marks 1

17. Class Y :: 90 oC , Class C :: ?
A. 110 oC
B. 130 oC
C. 225 oC
D. 95 oC

Answer C

Marks 1

18. While selecting a gas, for circuit breaker, the property of gas that should be considered is
A. high dielectric strength
B. non-inflammability
C. good arc quenching property
D. all of the above

Answer D

Marks 1

19. In a Townsend discharge, the current increases gradually as a function of the __________
A. frequency
B. charge on electron
C. applied voltage
D. work function

Answer C

Marks 1

20. In addition to insulating properties, SF6 possesses excellent __________ properties.
A. magnetic
B. arc quenching
C. electric
D. conducting

Answer B

Marks 1

SET 3 of Insulating materials and their properties and applications mcq's

21. Disruptive discharge voltage is the voltage which produces the loss of ______strength of insulation.
A. dielectric
B. magnetic
C. electric
D. mechanical

Answer A

Marks 1

22. The breakdown of insulation of the cable can be avoided economically by the use of
A. inter-sheaths
B. insulating materials with different dielectric constants
C. both (A) and (B)
D. none of the above

Answer C

Marks 1

23. Which of the following factors do affect the resistivity of metal ?
A. Age hardening
B. Alloying
C. Temperature
D. All of the above

Answer D

Marks 1

24. Which of the following insulating materials can tolerate maximum temperature?
A. mica
B. ceramics
C. glass
D. All of the above

Answer D

Marks 1

25. While selecting a gas for circuit breaker, the property of gas that should be considered is
A. high dielectric strength
B. non-inflammability
C. all of the above
D. none of the above

Answer C

Marks 1
 
26. Electrical Machine's slot liners:: cotton tapes , Capacitor body :: ?
A. plastic
B. wood
C. ceramic
D. rubber

Answer C

Marks 1

Click here to read part 1 of insulatng materials..

Click here to read part 2 of insulatng materials..

Click here to read part 3 of insulatng materials..





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