UNIT-V ELECTROMAGNETISM & MAGNETIC PROPERTIES OF MATERIALS
SHORT ANSWER QUESTIONS:
1. Define electric susceptibility and polarizability.
2. What is internal field? Give an expression for Clausius-Mosotti relation.
3. Define the terms electric displacement vector and susceptibility.
4. Derive the expression for ionic polarizability in a dielectric material.
5. What is orientation polarization? Derive the expression for orientation polarizability.
6. Explain the terms:
a) Dielectric constant
b) Electric susceptibility and
c) Displacement vector
7. What is Piezo-electricity?
8. Explain Ferro-electricity.
9. A paramagnetic material has magnetic field intensity 2x104 A/m. If the susceptibility of the material is 3.0x10-4 , calculate the flux density.
10. Give differences between soft and hard magnets.
11. Explain the terms:
a) Magnetic induction
b) Magnetic susceptibility
12. Define the terms:
a) Permeability of a medium
b) Intensity of Magnetization
13. Define the terms magnetic induction (B), magnetization (M) and magnetic field (H). Obtain an expression relating to these quantities.
14. Define Gauss Law.
15. Explain Faraday’s Law.
16. Write Maxwell equations in Differential and integral forms.
LONG ANSWER QUESTIONS:
1.
a) Derive a relation between electronic polarization and electric susceptibility of the dielectric medium.
b )Derive Clausius-Mosotti equation..
2.
a) What is internal field? Describe Lorentz method to calculate the internal field of a cubic structure.
b) Explain briefly Piezoelecctricity and Ferro-electricity..
3.
a) Derive the expressions for electronic polarizability in a dielectric.
b) Explain Piezoelecctricity in dielectrics.
4.
a) Derive Clausius-Mosotti relation in dielectrics..
b) Write a note on Ferro-electricity.
5.
a) Derive an expression for the internal electrical field in dielectrics exposed to a external electric field.
b) Distinguish between piezo and ferroelectric effects.
6.
a) Derive expressions for electronic and ionic polarizations.
b) Describe Lorentz method to calculate the internal field of a dielectric material.
7.
a) Distinguish between Para, Ferro and Ferri magnetic materials.
b) Distinguish between soft and hard magnetic materials.
8.
a) Explain Hysteresis curve based on domain theory.
b) Explain how ferrites are superior to ferromagnetic materials? Discuss hard and soft magnetic materials?.
9. Draw and explain B-H curve for a ferromagnetic material
10.
a) Explain the distinguishing features of ferro, antiferro and ferromagnetic materials.
b) Explain in detail domain theory of Ferromagnetism.
11. Define Gauss law and explain it.
12. State and explain Faraday’s law.
13. Define Maxwell equations and obtain Maxwell equations in integral and differential forms.
14. State and explain continuity equation.
15. What is hysteresis? What is the importance of this curve? Explain