Electrical Materials MCQs Part-4

Electrical Materials MCQs

1. Clausius Mossotti equation is valid for an internal field constant of_____.

a. 1

b. ¼

c. ½

d. None of the above

 

2. Ferrites have_____.

a. High specific gravity compared to iron

b. Low resistivity

c. Low eddy current loss

d. Low copper loss

 

3. Loss in a dielectric may occur due to______.

a. Ionization

b. Conductivity

c. Polarization

d. Any of the above

 

4. Dielectric loss due to ionization is peculiar to______.

a. Gaseous dielectrics

b. Non-uniform dielectrics

c. Non-metallic dielectrics

d. Non-ferrous dielectrics

 

Magnetic Properties of Materials

 

5. The temperature of the anti-ferromagnetic-to-paramagnetic transition is called_____.

a. Debye temperature

b. Neel temperature

c. Curies-Weiss temperature

d. Antiferromagnetic Curie temperature

 

6. The transition from the ferromagnetic to the paramagnetic state is named after_____.

a. Debye

b. Neel

c. Curie-Weiss

d. Curie

 

7. A suitable material for audio and TV transformers is______.

a. Very pure Fe

b. Fe-30% Ni

c. Fe-4% Si

d. Ferrite

 

8. Magnetic susceptibility is_____.

a. Proportional to temperature but independent of magnetizing field

b. Proportional to temperature but inversely proportional to magnetizing field

c. Inversely proportional to temperature but independent of magnetizing field

d. Inversely proportional to both temperature and magnetizing field

 

9. For a compass needle and computer disc drive_____.

a. Soft magnetic material is required

b. Hard and soft magnetic materials respectively are required

c. Hard magnetic material is required

d. Soft and hard magnetic materials respectively are required

 

10. For high speed of reading and storing the in formations in a computer, the use is made of______.

a. Ferromagnetics above 768⁰C

b. Ferrites

c. Pyroelectrics

d. Piezoelectrics

 

11. Magnetic susceptibility of material is -1. It belong to the kind of solid known as ______/

a. Garnet

b. Anti-ferromagnetic

c. Superconductor, type I

d. Ferrite

 

12. Magnetostriction is a phenomenon which occurs in_______.

a. Ferromagnetic materials

b. Ferrimagnetic materials

c. Antiferromagnetic materials

d. Paramagnetic materials

 

13. Bohr magneton is defined as______.

a. Magnetic moment of an electron orbital motion

b. Magnetic moment of an electron spin

c. Magnetic moment of an nucleus spin

d. None of the above

 

14. At Neel temperature_____.

a. Susceptibility is maximum

b. Susceptibility is minimum

c. Permeability is maximum

d. Permeability is minimum

 

15. Magnetostriction is the phenomenon_______.

a. Of changes in physical dimensions of ferromagnetic materials during magnetization

b. Of changes in permeability of ferromagnetic material during magnetization

c. Of producing magnetism in conductor

d. Of producing electricity in ferromagnetic materials

 

16. The converse of magnetostriction effect is_______.

a. Bitter powder effect

b. Curie effect

c. Villari effect

d. Thompson effect

 

17. The magnetic permeability is maximum for______.

a. Dimagnetic materials

b. Ferromagnetic materials

c. Paramagnetic materials

d. None of the above