PH3254 Physics for Electronics Engineering Previous Year Question Papers - Anna University

UNIT I: Crystallography

Part A (2 Marks)

• Define a Unit Cell. List the seven crystal systems.
• What are Miller Indices? State their significance.
• Define Atomic Radius and Coordination Number.
• Differentiate between primitive and non-primitive cells.

Part B (13/16 Marks)

• Crystal Structures: Explain SC, BCC, FCC, and Diamond Cubic structures. Derive their packing factors.
• Miller Indices: Explain steps to determine Miller indices and derive the interplanar distance formula for (hkl) planes.
• HCP Structure: Discuss Hexagonal Close Packed structure. Derive c/a ratio and packing factor.

UNIT II: Electrical and Magnetic Properties of Materials

Part A (2 Marks)

• State the postulates of Classical Free Electron Theory.
• Define Fermi distribution function and its temperature dependence.
• What are Giant Magneto Resistance (GMR) devices?
• Define Drift Velocity and Mobility of electrons.

Part B (13/16 Marks)

• Classical Theory: Derive expressions for electrical and thermal conductivity. Prove Wiedemann–Franz Law.
• Density of States: Derive expression for density of energy states in metals.
• Magnetic Materials: Explain origin of ferromagnetism and exchange interaction.
• GMR Devices: Explain construction and working of GMR-based magnetic storage devices.

UNIT III: Semiconductors and Transport Physics

Part A (2 Marks)

• Distinguish between direct and indirect bandgap semiconductors.
• Define Hall Effect and state its applications.
• Differentiate between Ohmic contacts and Schottky diodes.

Part B (13/16 Marks)

• Carrier Concentration: Derive expressions for electron and hole concentration in intrinsic and extrinsic semiconductors.
• Hall Effect: Derive Hall coefficient and explain experimental determination.
• Fermi Level: Explain variation of Fermi level with temperature and doping (n-type & p-type).

UNIT IV: Optical Properties of Materials

Part A (2 Marks)

• State properties and requirements of light detectors.
• What are the advantages of LEDs over conventional sources?
• Define Photovoltaic Effect.

Part B (13/16 Marks)

• Optoelectronic Devices: Explain principle, construction, and working of LED and Solar Cell.
• Quantum Wells: Discuss optical absorption and emission in quantum wells with electric field effects.
• Photovoltaic Devices: Explain I–V characteristics and efficiency of solar cells.

UNIT V: Nano Devices

Part A (2 Marks)

• What is Quantum Confinement?
• Define Spintronics and state its significance.
• What is a Quantum Dot? How is its color controlled?

Part B (13/16 Marks)

• Quantum Structures: Explain density of states in quantum wells, wires, and dots.
• Carbon Nanotubes (CNTs): Describe structure, properties, and applications.
• Single Electron Transistor (SET): Explain working principle and conditions for single-electron tunneling.

Most Repeated / High-Weight Questions

Crystal structures + packing factor derivations (Unit I), Classical electron theory + Wiedemann-Franz law (Unit II - high weight), Hall effect + Fermi level + carrier concentration (Unit III - high weight), LED + solar cell + quantum wells (Unit IV), Quantum confinement + carbon nanotubes (Unit V).