Electrical Materials MCQs Part-2

Electrical Materials MCQs

1. Which of the following materials is used for making helicopter structure?

a. Thoriated nickel alloy

b. carbon fibre polymeric composite

c. Stetite

d. Pure aluminium

 

2. Point imperfections, during interaction with each other,_____.

a. Are thermodynamically stable

b. Are not affected at all

c. Lower their total energy

d. Both (a) and (b)

 

3. The impedance may be minimized by_______.

a. Surface treatment

b. Making metal in fibre form

c. Thermal energy

4. All of these

 

4. The forces involved in the chemical bonding are_____.

a. Coulomb’s forces

b. Plank’s forces

c. Newton’s forces

d. Paulis’ forces

 

5. The nature of bond is governed by_____.

a. Basis of filling of space lattice

b. Orientation of crystal

c. Electron structure of the atom

d. Geometry of unit cell

 

6. A material is most stable when its potential energy is_____.

a. Zero

b. Minimum

c. Infinite

d. Maximum

 

7. The ACSR (Aluminium conductor steel reinforced) is an example of______.

a. Whisker reinforced composite

b. Bulk moulding compound

c. Metal fibre composite

d. Agglomerated composite

 

8. The structure of quartz (SiO₂) is______.

a. Orthorhombic

b. Face centered cubic

c. Body centered cubic

d. Hexagonal

 

9. Crystals like diamond and silicon are brittle, because_____.

a. They contain very few dislocations

b. The stress to move a dislocation is high

c. They are non-crystalline

d. They contain no dislocations

 

10. The crystal structure of most of the common metals is______.

a. Linear

b. Orthorhombic

c. Cubic

d. Hexagonal

 

11. In a crystal lattice, what are the vacancies created by the absence of certain atoms known as?

a. Crystal defects

b. Pauli defects

c. Schottky defects

d. Hertz defects

 

 Dielectric properties of Materials

 

12. Dielectric materials _______.

1. Have high specific resistance

2. Have positive temperature coefficient of resistive

3. May belong to the ceramic family

4. Exists only in solid and liquid form but not in gas form

Which of the above characteristics of dielectric material holds true?

a. 1 and 3 only

b. 2 and 4 only

c. 1, 3 and 4 only

d. 2, 3 and 4 only

 

13. Which of the following dielectric material possess maximum dielectric strength?

a. Mica

b. Glass

c. CO₂

d. Bakelite

 

14. The dielectric strength of a natural rubber is 40 kV/mm at 60 Hz. What is the thickness of insulation on a wire carrying 33 kV to sustain the breakdown?

a. 0.0082 mm

b. 0.82 mm

c. 8.2 mm

d. 0.082 mm

 

15. A good insulating material should have______.

a. Low dielectric strength but high dielectric constant

b. Low dielectric strength and dielectric constant

c. High dielectric strength and dielectric constant

d. High dielectric strength but low dielectric constant