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
