PH3251 Materials Science Important Questions

PH3251 Materials Science Important Questions

Unit 1

1. Explain the concepts of Nucleation and growth. Describe the Homogeneous and Heterogeneous process of nucleation with necessary diagrams.
2. Discuss in detail the edge and screw dislocations with neat diagram. Give a note on their effect on crystal stability.
3. Describe the various types of crystal imperfections in detail.
4.  Explain the arrangement of atoms in FCC and HCP unit cell with neat sketch.
5. With neat diagram, explain BCC and FCC crystal structures.
6. Explain grain and twin boundary imperfections in crystals.
7. Explain homogeneous and heterogeneous nucleation processes in crystal growth.

Unit 2

1. Derive expression for electrical conductivity and thermal conductivity on the basis of classical free electron theory.
2.  Explain the ferromagnetic domain theory in detail and discuss exchange interaction in ferromagnetic materials with suitable example.
3. Derive an expression for electrical and thermal conductivities of metal. Using classical free electron theory.
4. Arrive the formula for density of states in metals using quantum free electron theory.
5. Derive the expression for density of energy states.
6.  Explain domain theory of ferromagnetism and energies involved in domain growth.

Unit 3

1. Explain the variation of carrier concentration in n-type and p-type semiconductor with temperature.
2. What is Hall effect? Derive an expression for Hall Coefficient and Hall angle. Describe an experiment for the measurement of the hall co-efficient. Mention its applications.
3. Derive an expression for carrier concentration in intrinsic semiconductor.
4. Explain the theory of Hall effect and determine the Hall Voltage and Hall Co-efficient for p type semiconductor.
5. Derive an expression for electron and hole concentration in intrinsic semiconductor.
6. Explain Hall effect phenomena and obtain an expression for Hall coefficient.

Unit 4

1. Briefly discuss the modulator and switching devices with neat sketch. Also give an explanation for optical process in quantum wells.
2.  Explain with suitable diagram how laser action is achieved in homo junction and hetero junction diode laser.
3. Explain the working mechanism of P-N light detectors.
4. Describe the principle and working of LED.
5. Elaborate the principle and working of a Solar cell.
6. Explain the working of Laser diode with energy level diagram.

Unit 5

1. Explain the principle, construction and working of single electron transistor in detail.
2. Explain the types, properties and applications of carbon nanotubes in detail.
3. Write note a Zener-Bloch oscillations, resonant tunnelling and quantum interference effect.
4. Describe the density of states in quantum well, quantum wire and quantum dot structure.
5. Explain Quantum confinement and Quantum structures with figures.
6. Explain in detail the principle of single electron transistor and its performance.