JNTU
JNTU B.Tech I Year ENGINEERING PHYSICS Previous Question Paper (May - 2018 - R15)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART-A
Define Coordination number and Packing factor.
Answer
The Coordination number is the number of nearest neighboring atoms touching a specific atom in a crystal lattice. The Packing factor (or Atomic Packing Factor) is the ratio of the volume occupied by atoms in a unit cell to the total volume of the unit cell.
Sketch the (100), (110) and (111) planes in a simple Cubic structure.
Answer
In a simple cubic structure: The (100) plane is a face parallel to the yz-plane passing through the origin. The (110) plane is a diagonal plane passing through the z-axis and the face diagonal of the xy-plane. The (111) plane is an inclined plane intersecting all three axes at unit distance from the origin.
Define Fermi Energy.
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State the Bloch theorem.
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Define the Dielectric constant of a material.
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Explain the nature of superconductor in the magnetic field.
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What is diffraction grating?
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An optical fiber having refractive indices of 1.6 and 1.59 for core and cladding respectively is placed in water of refractive index 1.33. Find the Numerical Aperture of the fiber.
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Write is the significance of Surface to Volume ratio in nanomaterials.
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A hall with volume 6000 m3 has reverberation time 1.2 sec. Find the total absorption in the hall.
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PART-B
Distinguish between Ionic, Covalent and Metallic bonds in solids.
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Obtain the expression for the inter planar spacing of the orthogonal crystal system.
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Describe the crystal structure of diamond.
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State the Bragg’s law of X-ray diffraction. Discuss the Laue method of X-ray diffraction for the determination of crystal structure.
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What are Matter waves? How they are different from electromagnetic waves.
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Formulate Schroedinger’s Time Independent wave equations for a particle in one dimensional infinite square well potential and obtain the expression for its energy values.
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Distinguish between Maxwell – Boltzmann, Bose Einstein and Fermi – Dirac distributions.
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Draw E-K curves for an electron in periodic potential and explain how it leads to formation of energy bands in solids.
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What is density of polarization? Obtain a relation between polarization density and electric displacement vector.
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Define electronic polarization. Derive an expression for electronic polarizability.
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Distinguish between dia, para, ferro, antiferro and ferri magnetic materials.
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Write two applications of ferrimagnetic materials.
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What are type I and type II super conductors.
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Explain the phenomenon of interference in reflected light from a thin film. Obtain the condition for maxima and minima.
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How this phenomenon is used to reduce the heating effect of sun light from the roof of a building.
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Write down the characteristics of Laser light.
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Describe the construction and working of He-Ne laser with suitable diagrams.
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What are direct and indirect band gap semiconductors?
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State and explain the Hall-effect and derive the expression for Hall coefficient.
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The Hall coefficient of specimen is 3.66×10-4 m3/coul. Find the number of charge carriers present per unit volume of the specimen.
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Derive an expression for the concentration of electrons in an intrinsic semiconductor.
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Describe the Sol-Gel method of preparation of Nanomaterials.
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