UNIT- I CONDUCTING MATERIALS
PART – A ( 2 Marks)
1. What are the postulates of free electron theory?
2. Define drift velocity and mean free path.
3. Define relaxation time and collision time.
4. Define electrical conductivity.
5. Define thermal conductivity.
6. State Wiedemann- Franz law. Give the value of Lorentz number.
7. What are the merits and demerits of free electron theory?
8. Define density of energy states in metal.
9. Define Fermi energy and give its importance.
10. Write down Fermi –Dirac distribution function.
11. Write down the difference between the quantum and classical free electron
12. Define carrier concentration of metals.
13. The Fermi temperature of a metal is 24600k.calculate the Fermi velocity.
14. Use Fermi function to obtain the value of f(E) for E-EF = 0.01eV at 200K
15. The thermal conductivity of copper at 20oC is 390 wm-1k-1 and 5.87x107 mho/m
respectively. Calculate the Lorentz Number.
PART – B ( 16 MARKS)
1.1 Deduce the mathematical expressions for electrical conductivity and thermal conductivity of a
material and hence obtain widemann - franz law. (6+8+2)
1.2 Derive an expression for the density of states and based on that calculate the carrier concentration in
1.3 Write Fermi-Dirac distribution function. Explain how Fermi function varies with temperature.
Evaluate the Fermi function for energy KT above the fermi energy. (2 + 10 + 4)
UNIT-2 SEMI CONDUCTING MATERIALS
PART – A ( 2 Marks)
1. What are semi conductors?
2. What are called elemental and compound semi conductors?
3. What are the properties of semi conductor?
4. What are the differences between intrinsic and extrinsic semiconductors?
5. What do you mean by doping?
6. What is meant by band gap in semi conductor?
7. Compare p & n-type semiconductors.
8. What is donor and acceptor. Give examples for each?
09. Define Fermi level in case of semi conductors. Mention its position in intrinsic
and extrinsic semiconductors at 0k
10. What are the applications of Hall Effect?
11. The intrinsic carrier density is 1.5x1016/m3. if the electron and hole mobilities are
0.13 and 0.05 m2v-1s-1. Calculate its electrical conductivity?
PART – B ( 16 MARKS)
2.1 Derive an expression for the density of electrons and holes in an
intrinsic semi conductor (8+8)
2.2 (i) Discuss the variation of Fermi level with temperature in an intrinsic semi
(ii) Describe the method of determining the band gap of an intrinsic
2.3 Discuss the carrier concentration, variation of Fermi level with temperature in
case of p-type and n-type semiconductors for high and low doping levels
2.4 What is Hall Effect? Derive an expression for hall coefficient. Describe an
experimental setup for determining the hall coefficient. (2+8+6)
UNIT – III MAGNETIC MATERIALS & SUPER CONDUCTING MATERIALS
PART – A (2 Marks)
1. Define – Magnetic field intensity.
2. Define the terms
(i) Magnetic permeability (ii) Magnetic susceptibility
3. Define the terms
(i) Retentivity (ii) Coercivity
4. What do you mean by magnetic dipole? How will you define dipole
5 What is domain? What are domain walls?
6. What is Bohr Magneton? Give its value.
7. Distinguish between Dia, Para & Ferro magnetic materials.
8. What is Hysteresis? What are Hysteresis losses?
9. What are Hard & Soft magnetic materials?
10. What are Ferrites? Mention few applications of Ferrites.
11. Define Superconductivity. What are Superconducting materials?
12. What is critical or Superconducting transition temperature?
13. What is Meissner effect?
14. What is persistent current?
15. Distinguish between Type I & Type II superconductors.
16. What are High temperature superconductors? Give examples.
17. What is DC & AC Josephson Effect?
18. What is SQUID?
19. Calculate the critical current in a wire made up of lead having diameter of 1 mm at 4.2K. Critical
temperature of lead is 7.18K & Hc at 0K is 6.5x 104 Amp/m.
PART – B (16 MARKS)
3.1 Distinguish between dia, para, ferro and anti ferro magnetic materials.
Mention their properties and applications (16 Marks)
3.2 Explain domain theory of ferromagnetism. Using that how will you explain the
properties of ferromagnetic materials (16 Marks)
3.3 Explain the magnetic principle involved in data storage and hence explain
the magnetic memories (i) Magnetic tapes (ii) Floppy disk and (iii) Hard disk
3.4 Discuss the properties of super conductors ( 6 Marks )
Distinguish between Type – I and Type- II Super conductors (6 Marks)
Write a note on high temperature super conductors (4 Marks)
3.5 Write a short note on
(i) Meissner Effect (ii) Josephson Effect (iii) SQUID and (IV) Magnetic levitation
UNIT IV DIELECTRIC MATERIALS
PART – A (2 MARKS)1. What are dielectric materials?
2. Define dielectric constant.
3. What is dielectric polarisation?
4. Define – Polarisation vector.
5. Distinguish between polar & non-polar molecules.
6. Mention the types of polarisation in dielectric.
7. What do you mean by Lorentz field?
8. Define – Dielectric Loss.
9. Define – Dielectric Breakdown.
10. Mention the various types of breakdown in Dielectrics.
11. What are the properties of Dielectric materials?
12. Mention the applications of Dielectric materials?
13. What is ferro electricity? Give few examples of ferro electric materials.
14. Calculate the electronic polarisability of an isolated Se atom, if the atomic radius of Se atom is
PART – B ( 16 MARKS)
4.1 Explain the different types of polarization mechanisms involved in dielectric
materials (16 Marks)
4.2 What is meant by local field in a dielectric and how it is calculated for cubic structure? Deduce the
Claussius- Mosotti equation ( 16 Marks)
4.3 What are the different types of dielectric breakdown occurs in a dielectric medium? Discuss in detail,
the various types of dielectric breakdown (2 +14)
UNIT-V NEW ENGINEERING MATERIALS
PART –A ( 2 MARKS)
1. What are metallic glasses?
2. What are the properties of metallic glasses?
3. What are the advantages of using metallic glasses as transformer core
4. Write any four applications of metallic glasses .
5. What is shape memory effect?
6. What are the characteristics of shape memory alloys?
7. Give any four applications of shape memory alloys.
8. What are the advantages and disadvantages of shape memory alloys?
9. What are Nano phase materials ? Give examples.
10. What are the techniques used for synthesis of nano materials ?
11. What are the properties of nano phase materials?
12. What are the types of carbon nano tubes?
13. What are the structures of carbon nano tubes?
14. What are the properties of carbon nano tubes?
15. What are the applications of carbon nano tubes?
PART- B (16 MARKS)
5.1 Give a detailed account on metallic glasses, their production, types,
properties and applications (16 Marks)
5.2 What are nano-phase materials? Discuss the synthesis, preparation, properties
and applications of nano-phase materials (16 Marks)
5.3 What are shape memory alloys? Write their characteristics. List out any four applications of shape
memory alloys (16 Marks)
5.4 Describe the structure, fabrication, properties and applications of carbon
nano tubes (CNT). (16 Marks)