Manonmaniam Sundaranar University

B.Sc Physics — Semester 6

April 2026 Examination

Solid State Physics — Important Questions

Unit-wise Important Questions Based on Previous Year University Question Papers

Solid State Physics is one of the most important and scoring subjects in B.Sc Physics Semester 6 under Manonmaniam Sundaranar University. Questions from crystal structures, superconductivity, dielectric theories, bonding in solids, and nanomaterials are frequently repeated in university examinations.

This article provides unit-wise important questions collected from previous year university question papers and repeated examination patterns. Students appearing for the April 2026 Semester Examination can use this post for quick revision, last-minute preparation, and identifying highly important university topics.

⭐ Most Important Repeated Topics

• Bragg’s Law Derivation
• NaCl Crystal Structure
• Clausius-Mossotti Relation
• Meissner Effect
• BCS Theory of Superconductivity
• CVD and Sol-Gel Methods

These questions have appeared repeatedly in university examinations and are considered highly important for Semester 6 students.

Unit 1: Crystal Structure

Part A (1 mark)

• Effective number of atoms in SC, BCC, FCC unit cells
• Miller indices problems (finding intercepts from indices and vice versa)
• Coordination number of BCC crystal
• Bragg's law equation: nλ = 2d sinθ

Part B (5 marks)

• State and explain Bragg's law for X-ray diffraction
• Explain the seven crystal systems and Bravais lattices
• Draw the structure of NaCl and Diamond

Part C (8 marks)

• Draw and explain NaCl structure in detail
• Derive Bragg's law of X-ray diffraction
• Explain SC, FCC, BCC, HCP structures with diagrams and atomic packing factors
• Define Miller indices — procedure with example, including a plane with intercepts a, b, c

Unit 2: Bonding in Solids

Part A (1 mark)

• Types of primary bonds (ionic, covalent, metallic)
• Atoms of solid Ar held by Van der Waals/dispersion force
• Formation of solid helium — dispersion bond
• Madelung constant for NaCl (1.748)
• Cohesive energy of NaCl (~786 KJ)

Part B (5 marks)

• Comparison between ionic and covalent solids
• Van der Waals bond in crystals
• Hydrogen bonding
• Estimate cohesive energy of ionic solids

Part C (8 marks)

• Explain ionic, covalent, and metallic bonds with nature of interactions
• Define cohesive energy; find it for ionic solids/NaCl
• Evaluate Madelung constant for NaCl
• Explain types of bonding in crystals (all three types)

Unit 3: Dielectrics & Magnetism

Part A (1 mark)

• Gold is a diamagnetic material
• Domain formation → Ferromagnetism
• Materials lacking permanent magnetic dipoles → Diamagnetic
• Cobalt → Ferromagnetic
• Dielectric materials do not have free electrons

Part B (5 marks)

• Langevin's classical theory of paramagnetism
• Define dielectrics and types of electric polarization
• Weiss theory of paramagnetism
• Domain theory of ferromagnetism / antiferromagnetism
• Electronic polarizability — expression

Part C (8 marks)

• Derive Clausius-Mossotti relation
• Discuss Weiss theory of paramagnetism
• Explain Langevin's classical theory of diamagnetism
• Define internal field and derive Clausius-Mossotti relation
• Ionic and orientation polarization

Unit 4: Superconductivity

Part A (1 mark)

• Superconductor is a perfect diamagnetic material
• BCS theory — Bardeen, Cooper, Schrieffer
• In superconducting state: entropy decreases, thermal conductivity decreases
• Hard superconductors → incomplete Meissner effect
• Cooper pair = two electrons connected through a phonon
• Below transition temp → zero resistance + diamagnetism

Part B (5 marks)

• State and explain Meissner effect
• General properties of superconductors
• Type I and Type II superconductors
• BCS theory (brief)
• AC and DC Josephson effect applications

Part C (8 marks)

• Write a note on Type-I and Type-II superconductors (comparison)
• Briefly discuss BCS theory of superconductivity
• Derive London equations in superconductors
• Explain high temperature superconductors

Unit 5: Nanomaterials

Part A (1 mark)

• CNTs = Carbon Nanotubes
• Sol-gel method = Bottom-up approach
• Top-down: Bulk → Power → Nano-particles
• Graphene = honeycomb sheet of carbon atoms
• Fullerenes = carbon allotrope; molecule not in form of hollow sphere/tube/ellipsoid

Part B (5 marks)

• What are nanomaterials? Classification modes
• Carbon nanotubes — structure and properties
• Characterization of nanoparticles

Part C (8 marks)

• Chemical vapour deposition (CVD) and sol-gel technique
• Properties and applications of nanomaterials
• Ball milling method
• Synthesis of nanoparticles by electrodeposition
• Properties and applications of graphene / carbon nanotubes

Disclaimer

This material is prepared only for educational and revision purposes based on previous year university question papers and commonly repeated topics. The questions listed here are not official university predictions or guaranteed examination questions. Students are advised to study the complete syllabus prescribed by Manonmaniam Sundaranar University for Semester 6 Solid State Physics.