Materials And Components MCQ Questions & Answers

31

The piezoelectric effect is the polarization of a dielectric under the influence of

A) Light B) Mechanical stress C) Electrical stress D) Heat

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Answer & Solution

Answer: Option B

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32

The superconductivity is due to

A) The crystal structure having no atomic vibration at 0°K B) All electrons interact in the super-conducting state C) The electrons jump into nucleus at 0°K D) None of the above

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Answer & Solution

Answer: Option A

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33

The dielectric strength of gaseous dielectric depends on which of the following factors?

A) Pressure B) Uniformity of applied electric field C) Frequency of applied field D) All of the above

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Answer & Solution

Answer: Option D

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34

Match List-I with List-II and select the correct answer using the options given below:

List-I (Optical devices)	List-II (Electrical/optical characteristics)
a. GaAs	1. Emits monochromatic light of low intensity
b. Solar cell	2. Consumers electrical power due to the incident light
c. Photo Diode	3. Deliver power to a load
d. LED	4. Emits monochromatic light of light intensity

A) a-4, b-3, c-1, d-2 B) a-3, b-4, c-2, d-1 C) a-4, b-3, c-2, d-1 D) a-3, b-4, c-1, d-2

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Answer & Solution

Answer: Option C

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35

A large value of the exchange interaction energy in a ferromagnetic material implies.

A) Large saturation magnetization B) High Curie temperature C) High melting point D) Large diamagnetic susceptibility

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Answer & Solution

Answer: Option A

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36

The resistance of a metallic wire would

A) increase as the operation frequency increase B) decrease as the operating frequency increase C) remain unaffected on increasing the operation frequency D) initially increase up to a certain value of the operating frequency and then decrease with increase in operating frequency

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Answer & Solution

Answer: Option B

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37

Which of the following represent the properties of carbon nanotubes?
1. High electrical conductivity
2. Very high tensile strength
3. High thermal conductivity
4. Low thermal expansion coefficient
Select the correct answer using the options given below:

A) 1, 2 and 3 only B) 1, 2 and 4 only C) 1, 3 and 4 only D) 1, 2, 3 and 4

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Answer & Solution

Answer: Option D

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38

Materials which lack permanent magnetic dipoles are known as

A) Paramagnetic B) Diamagnetic C) Ferromagnetic D) Ferri magnetic

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Answer & Solution

Answer: Option B

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39

A 'hole' in a semiconductor has
1. Positive charge equal to the electron charge
2. Positive mass equal to the mass of the electron
3. An 'effective mass' greater than the effective mass of electron
4. Negative mass and positive charge equal to the charge in nucleus

A) 1, 2, 3 and 4 B) 1 and 3 only C) 2 and 4 only D) 3 and 4 only

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Answer & Solution

Answer: Option B

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40

The magnetic field at which a superconductor remains in its superconducting state at a temperature less than the transition temperature is

A) Zero B) Greater than the critical field corresponding to the given temperature C) Less than the critical field corresponding to the given temperature D) Equal to the critical field corresponding to the transition temperature

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Answer & Solution

Answer: Option C

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Materials And Components MCQ Questions & Answers | ECE