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MCQs on Insulating Materials | Properties and applications | Part 1





Objectives on Insulating materials and their properties and applications

 

This sets of objective questions or MCQs more focuses on insulating materials and their properties and applications in part 1....

Click here to read part 1 of Dielectric Constants, Dipole moment, Polarization

SET 1 of Insulating materials and their properties and applications mcqs 

1. …… insulators are commonly used for overhead power lines.
A.Porcelain
B.Toughened glass
C.both (A) & (B)
D.none of above

Answer C


2.………….. is the main constituent of glass.
A.Al2O3
B.B2O3
C.SiO2
D.Fe2 O3

Answer C

3.Solid insulating material regains its dielectric strength-------------
A.fully
B.partially
C.90.00%
D.none of the above

Answer D

4.Liquid insulating material regains its dielectric strength-------------
A.fully
B.partially
C.can not regain
D.(A) or (B) depending on conditions

Answer B

5.Gaseous insulating material regains its dielectric strength-------------
A.fully
B.partially
C.can not regain
D.(A) or (B) depending on conditions

Answer A

Marks 1

 

6.Following is responsible to start ionization processA dust particle
B.ultra violet ray
C.initiating electron
D.positive ion

Answer C

Marks 1

7.-----------(insulating material) is used as slot liners in rotating machines.
A.Asbestos tape
B.Glass tape
C.Paper
D.Pressboard

Answer A

Marks 1

8.Which of the following is a polar dielectric ?
A.Teflon
B.Quartz
C.Nylon
D.Polyethylene

Answer C

Marks 1

9.Class Y insulation has limiting temperature of -------------- oC
A.105
B.120
C.90
D.155

Answer C

Marks 1

10.Which of the following is a non-polar dielectric?
A.Polystyrene
B.Phenolic plastics
C.Plasticized cellulose acetate
D.Castor oil

Answer A

Marks 1

SET 2 of Insulating materials and their properties and applications mcqs

 

11.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

Answer C

Marks 1

12.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

Answer C

Marks 1

13.The variety of paper used for insulation purpose is
A.blotting paper
B.rice paper
C.craft paper
D.mill-board.

Answer C

Marks 1

14.The Property of absorbing moisture from atmosphere by an insulating material, is known as--- .
A.solubility
B.porosity
C.hygroscopicity
D.viscosity

Answer C

Marks 1

15.Class H insulation can withstand temperature up to ----- oC.
A.180
B.90
C.155
D.130

Answer B

Marks 1

 

16.The factors which affect the breakdown voltage of oil are ------- .
A.impurity& bubbles
B.viscosity
C.temperature & molecular structure
D.All of the above

Answer D

Marks 1

17.In primary ionization, electron is liberated from, ---------- .
A.electrode surface
B.gas molecule
C.oil molecule
D.all

Answer B

Marks 1

18.In primary ionization, electron is liberated due to impact of ---------- .
A.free electron
B.positive ion
C.both
D.gas molecule

Answer A

Marks 1

19.Breakdown strength depends upon--------- .
A.electrode shape & size
B.temperature & pressure
C.distance of electrode from earth
D.all

Answer D

Marks 1

20.The breakdown voltage of non uniform field /electrode is ------------- uniform field.
A.less than
B.more than
C.dependent on condition of
D.equal to

Answer A

Marks 1

SET 3 of Insulating materials and their properties and applications mcqs

 

21.The factors affecting the breakdown voltage are --------- .
A.the thickness & density of materials
B.applied voltage magnitude and its waveform
C.frequency of supply & rate of change of voltage
D.all

Answer D

Marks 1

22.Varnish is applied toA increase resistance to atmospheric effect
B.to increase insulating properties
C.increase dielectric strength
D.all

Answer D

Marks 1

23.Class C insulation can withstand temperature up to ----- oC
A.130
B.90
C.155
D.above 180

Answer D

Marks 1

24.The Dielectric strength of mineral oil is –
A.30 kV/mm
B.10kV/mm
C.90kV/mm
D.None

Answer A

Marks 1
 
25.Calculate the breakdown strength of air, if gap between two spheres is 5.1 mm and the breakdown voltage is 12.2 kV(R.M.S. Value).
A.2.39 kV /mm
B.2.05 kV /mm
C.2.36 kV /mm
D.2.09 kV /mm

Answer A

Marks 1

26.The viscosity of transformer oil should be----- .
A.medium
B.low
C.large
D.Ver very large

Answer B

Marks 1

27.Varnish can be solution of resinous material in --------- .
A.alcohol
B.oil
C.volatile material
D.all

Answer D

Marks 1

28.Muscovite Mica is used in ------------------------- .
A.in radio, radio circuit capacitor & radio tubes, aeroplane spark plugs
B.in heating appliances like toasters, hot plates & electric irons
C.A & B
D.None

Answer A

Marks 1

29.Phlogopite Mica is used in ------------------------- .
A.in radio, radio circuit capacitor & radio tubes, aeroplane spark plugs
B.in heating appliances like toasters, hot plates & electric irons
C.(A) & (B)
D.none

Answer B

Marks 1

30. -------------------- is /are used in commutator segments.
A.Muscovite Mica
B.Phlogopite Mica
C.(A) & (B) both
D.Asbestos

Answer C

Marks 1

Click here to read part 1 of Dielectric Constants, Dipole moment, Polarization

 




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