Electrical Materials MCQs Part-3

Electrical Materials MCQs

1. In general, the effect of temperature on relative permittivity of a material is to______.

a. Maintain it

b. Increase it

c. Reduce it

d. All of these

 

2. Condensers to be used at high frequencies require a material whose loss angle is______.

a. Unity

b. Uniform

c. High

d. Low

 

3. In which of the following ceramics, the ionic character is maximum?

a. NaCl

b. SiO₂

c. ZnS

d. CaF₂

 

4. Which of the following is a basic refractory?

a. Chromite

b. SiO₂

c. Dolomite

d. Quartz

 

5. Which of the following is not a desirable property possessed by a good refractory?

a. Chemically inactiveness

b. High temperature withstanding capability

c. High electrical conductivity

d. Both (a) and (c)

 

6. The dielectric strength and dielectric constant of a ceramic should be______.

a. High

b. Low and high respectively

c. Low

d. High and low respectively

 

7. Which of the following items is not made of a ceramic material?

a. Reinforcing bar for cement concrete

b. Magnet

c. Insulators

d. Ferrite

 

8. Which of the following types of polarization occurs in multi-phase material?

a. Space charge polarization

b. Electronic polarization

c. Ionic polarization

d. Orientation polarization

 

9. The unit of relative dielectric constant is_______.

a. Dimensionless

b. FC^-1

c. CV^-1

d. Fm^-1

 

10. Among the common dielectric materials, the highest dielectric strength is possessed by_____.

a. Polyethylene

b. PVC

c. Mica

d. Transformer oil

 

11. During melting, the relative dielectric constant _____.

a. May increase or decrease

b. Always decreases

c. Always increases

d. None of the above

 

12. In the polarization versus field strength plot for a ferroelectric crystal, P_s stands for______.

a. Spontaneous polarization

b. Saturation polarization

c. Space charge polarization

d. None of the above

 

13. Expressed in base SI units, the electronic polarizability has the units_____.

a. A kg^-1 m^-2 s²

b. A² kg^-1 s⁴

c. C V^-1 m^-2

d. F-m²

 

14. The materials in which properties are independent and dependent on direction are called______.

a. Orthotropic and isotropic materials respectively

b. Anisotropic and Orthotropic materials respectively

c. Isotropic and anisotropic materials respectively

d. Anisotropic and isotropic materials respectively

 

15. Which of the following pairs does not represent piezoelectric materials?

a. Potassium dihydrogen phosphate, Rochelle’s salt

b. Lead zirconate, Sodium Neobate

c. Barium titanate, Quartz

d. Lead titanate, Rochelle’s salt