Materials And Components MCQ Questions & Answers

71

Intense magnetic field may be produced in a coil by using a

A) Normal metal with a large number of turns and sending a large current B) Type-I superconductor with a large number of turns and sending a large current C) Type-II superconductor with a large number of turns and sending a large current D) Type-II superconductor with a large number of turns but limiting the current density below a critical value

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Answer & Solution

Answer: Option B

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72

Which of the following are not the production methods for carbon nanotubes?
1. Electric arc discharge method
2. Laser vaporization method
3. Czochralski method
4. Metallization method
Select the correct answer using the options given below:

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

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Answer & Solution

Answer: Option C

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73

Superconductors are becoming popular for use in

A) generating very strong magnetic field B) manufacture of bubble memories C) generating electrostatic field D) generating regions free from magnetic field

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Answer & Solution

Answer: Option D

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74

Ceramic resonators use which one of the following?

A) Barium titanate B) Silicon C) Piezoelectric quartz crystal D) Zirconium titnate

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Answer & Solution

Answer: Option D

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75

Which of the following statements are correct for ceramic materials?
1. They are inorganic substances
2. They are brittle
3. They are good thermal insulators
Select the correct answer using the options given below:

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

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Answer & Solution

Answer: Option A

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76

A superconductor may be used for generating

A) Voltage B) Pressure C) Temperature D) Magnetic field

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Answer & Solution

Answer: Option D

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77

The difference between the number of atoms in a unit cell of a bcc crystal and an FCC crystal is

A) 1 B) 2 C) 4 D) 6

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Answer & Solution

Answer: Option B

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78

Ferromagnetic materials show hysteresis in B-H characteristics. As the magnetic field is increases slowly from zero value, what is the first process which sets in the material to give net magnetization?

A) Growth of favorably oriented domains at the cost of other domains by reversible boundary displacements B) Growth of favorably oriented domains at the cost of other domains by irreversible boundary displacements C) Domain wall orientation D) A combination of processes A and C above

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Answer & Solution

Answer: Option A

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79

In ruby laser, which of the following is true

A) ruby rod acts like resonant cavity B) It gives continuous laser beam C) electrical pumping is employed D) It's wavelength output is 6328 A°

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Answer & Solution

Answer: Option A

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80

For a permanent magnetic material

A) the residual induction and the coercive field should be large B) the residual induction and the coercive field should be small C) the area of hysteresis loop should be small D) the initial relative permeability should be large

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Answer & Solution

Answer: Option A

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Materials And Components MCQ Questions & Answers | ECE