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ECE : Materials and Components - Quiz(MCQ)
A)
Ionic crystals
B)
Ionic and valence crystals
C)
Ionic crystal, valence crystals and metals
D)
Ionic crystals, valence crystals, metal and vander wall crystals

Correct Answer : Option (D) :   Ionic crystals, valence crystals, metal and vander wall crystals

A)
The number of electrons-hole pairs generated per second due to thermal motion are equal to the number of electron-hole pairs lost per second due to recombination
B)
The number of electron-hole pairs generated per second due to thermal motion is always less than the number of electron-hole pairs lost per second due to recombination
C)
The number of electron hole pairs generated per second due to thermal motion is always more than the number of electron-hole pairs lost per second due to recombination
D)
All of the above

Correct Answer : Option (A) :   The number of electrons-hole pairs generated per second due to thermal motion are equal to the number of electron-hole pairs lost per second due to recombination

A)
Air capacitor
B)
Mica capacitor
C)
Paper capacitor
D)
Plastic film capacitor

Correct Answer : Option (B) :   Mica capacitor


Explanation : Energy stored is proportional to capacitance and capacitance is proportional to permittivity.

A)
permanent magnetic dipole do not exist
B)
permanent magnetic dipoles exist but the interaction between neighbouring dipoles is negligible
C)
permanent magnetic dipole moment may or may not exist
D)
permanent magnetic dipoles exist and the interaction between neighbouring dipoles is very strong

Correct Answer : Option (B) :   permanent magnetic dipoles exist but the interaction between neighbouring dipoles is negligible


Explanation : In paramagnetic materials interaction between neighbouring dipoles is negligible.

A)
Curie temperature
B)
Weiss temperature
C)
Neel temperature
D)
None of the above

Correct Answer : Option (C) :   Neel temperature

A)
low eddy current loss
B)
low resistivity
C)
a low copper loss
D)
higher specific gravity compared to iron

Correct Answer : Option (A) :   low eddy current loss


Explanation : Resistivity of ferrites is very high as compared to that of iron. Hence eddy curretns are much less.

A)
Low permittivity
B)
Permittivity same as that of air
C)
High permittivity
D)
Permittivity which is neither high nor low

Correct Answer : Option (C) :   High permittivity

A)
Air cored
B)
Cast iron cored
C)
Iron alloy cored
D)
Sheet steel cored

Correct Answer : Option (A) :   Air cored

A)
Increases
B)
Decreases
C)
Remains constant
D)
First decreases then increases

Correct Answer : Option (A) :   Increases

A)
About 10 K
B)
About 200 K
C)
About 600 K
D)
About 80 K

Correct Answer : Option (B) :   About 200 K