PH3251 Materials Science Important Questions
Unit 1
- Explain the concepts of Nucleation and growth. Describe the Homogeneous and Heterogeneous process of nucleation with necessary diagrams.
- Discuss in detail the edge and screw dislocations with neat diagram. Give a note on their effect on crystal stability.
- Describe the various types of crystal imperfections in detail.
- Explain the arrangement of atoms in FCC and HCP unit cell with neat sketch.
- With neat diagram, explain BCC and FCC crystal structures.
- Explain grain and twin boundary imperfections in crystals.
- Explain homogeneous and heterogeneous nucleation processes in crystal growth.
Unit 2
- Derive expression for electrical conductivity and thermal conductivity on the basis of classical free electron theory.
- Explain the ferromagnetic domain theory in detail and discuss exchange interaction in ferromagnetic materials with suitable example.
- Derive an expression for electrical and thermal conductivities of metal. Using classical free electron theory.
- Arrive the formula for density of states in metals using quantum free electron theory.
- Derive the expression for density of energy states.
- Explain domain theory of ferromagnetism and energies involved in domain growth.
Unit 3
- Explain the variation of carrier concentration in n-type and p-type semiconductor with temperature.
- 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.
- Derive an expression for carrier concentration in intrinsic semiconductor.
- Explain the theory of Hall effect and determine the Hall Voltage and Hall Co-efficient for p type semiconductor.
- Derive an expression for electron and hole concentration in intrinsic semiconductor.
- Explain Hall effect phenomena and obtain an expression for Hall coefficient.
Unit 4
- Briefly discuss the modulator and switching devices with neat sketch. Also give an explanation for optical process in quantum wells.
- Explain with suitable diagram how laser action is achieved in homo junction and hetero junction diode laser.
- Explain the working mechanism of P-N light detectors.
- Describe the principle and working of LED.
- Elaborate the principle and working of a Solar cell.
- Explain the working of Laser diode with energy level diagram.
Unit 5
- Explain the principle, construction and working of single electron transistor in detail.
- Explain the types, properties and applications of carbon nanotubes in detail.
- Write note a Zener-Bloch oscillations, resonant tunnelling and quantum interference effect.
- Describe the density of states in quantum well, quantum wire and quantum dot structure.
- Explain Quantum confinement and Quantum structures with figures.
- Explain in detail the principle of single electron transistor and its performance.