Objectives on Insulating materials and their properties and applications in part 5
This sets of mcq's contains questions on insulating materials its properties and their applications in part 5..
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SET 1 Insulating materials and their properties and applications mcq
1. Electrical Machine's slot liners:: cotton tapes, Dielectric material in capacitor:: ?
A. Tissue paper
B. Wood
C. Cotton
D. Resin
Answer A
Marks 1
2. In Townsend’s equation I = Io e αd, the term α is called as:
A. Townsend’s secondary ionization coefficient
B. Townsend’s primary ionization coefficient
C. Townsend’s tertiary ionization coefficient
D. None of the above
Answer B
Marks 1
3. The secondary ionization process depends on -
A. The liberation of secondary electrons at cathode as a result of positive ion bombardment
B. Photoelectric emission at cathode caused by photons in gas in region of anode.
C. Action of metastable particles at the cathode
D. All of the above
Answer D
Marks 1
4. Below breakdown voltage, all dielectric materials behave as -------- materials.
A. conducting
B. semiconducting
C. insulating
D. superconducting
Answer C
Marks 1
5. The ------ dielectric material recovers it dielectric strength partially, after its breakdown.
A. solid
B. gaseous
C. liquid
D. None of the above
Answer C
Marks 1
6. The phenomenon in which an electron emitted from a metal plate, when light of suitable wavelength fall on it, is called -----------
A. collision ionization
B. photo ionization
C. secondary ionization
D. none of the above
Answer B
Marks 1
7. Ionization current in liquids and gases, results from the flow of
A. photons
B. positive or negative ions
C. free electrons
D. all of these
Answer C
Marks 1
8. Highly purified liquid insulating materials are those
A. Which contain solid and water particles
B. Which are free from solid and water particles
C. Which are free from solid and water particles, as well as gases
D. none of these
Answer C
Marks 1
9. The -------- dielectric material recovers its dielectric strength fully, after its breakdown.
A. liquid
B. gaseous
C. solid
D. All of the above
Answer B
Marks 1
10. For photo ionization , the photons must have energy --------- its work function.
A. equal to or less than
B. equal to or greater than
C. less than
D. any of the above
Answer B
Marks 1
SET 2 Insulating materials and their properties and applications mcq
11. Primary ionization process includes
A. electron emission by collision
B. electron emission by photons
C. electron emission due to positive ion bombardment
D. any of the above
Answer A
Marks 1
12. Secondary ionization process includes
A. electron emission due to metastable and neutral atoms
B. electron emission by photons
C. electron emission due to positive ion bombardment
D. all of the above
Answer D
Marks 1
13. Breakdown voltage is generally expressed in
A. kV
B. mV
C. µV
D. µµV
Answer A
Marks 1
14. A good insulating material should possess
A. high humidity
B. high resistivity
C. medium conductivity
D. high loss tangent
Answer B
Marks 1
15. In gas pressure cable, -------------- gas is used under pressure.
A. nitrogen
B. oxygen
C. hydrogen
D. None of these
Answer A
Marks 1
16. High viscosity oil is used in
A. gas filled cables
B. switch gears
C. transformers
D. low tension cables
Answer A
Marks 1
17. Low viscosity oil is used in
A. gas filled cables
B. switch gears
C. transformers
D. low tension cables
Answer C
Marks 1
18. Mica and Micanite fall under ------------category of insulating material.
A. Class Y
B. Class C
C. Class H
D. Class E
Answer B
Marks 1
19. The density of gold is closer to density of
A. nichrome
B. tungsten
C. kanthal
D. paltinum
Answer A
Marks 1
20. -------- are also called three dimensional defects.
A. Surface defects
B. Volume defects
C. Line defects
D. All of the above
Answer B
Marks 1
SET 3 Insulating materials and their properties and applications mcq
21. Volume defects include
A. cracks
B. voids
C. inclusion
D. all of the above
Answer D
Marks 1
22. ----- is/are natural resins.
A. Amber
B. Shellac
C. Wood
D. All of the above
Answer D
Marks 1
23. Micanites are made of sheet glued with
A. amber
B. shellac
C. wood
D. all of the above
Answer B
Marks 1
24. Vacuum insulation is used in all of the following, EXCEPT
A. Particle accelerators
B. EHT of color TV
C. Field emission tubes
D. X-rays.
Answer B
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..
