I B.Tech - Regular Examinations, June 2009
First Year
APPLIED PHYSICS - SET NO: 1
(Regulation 2007)
Time : 3 hours |
Maximam Marks:80 |
Answer any FIVE Questions
1. (a) Explain the various types of bonding in solids with suitable examples.
(b) The Madelung constant of KCl is 1.75. Its neighbour separation is 0.314 nm.
Find the cohesive energy per atom. [Given that the Repulsive exponent value
= 5.77; Ionization energy of potassium = 4.1 eV; Electron affinity of chlorine
= 3.6 eV]
2.(a) Derive one-dimensional time independent Schrodinger wave equation for an
electron.
(b) Show that the energies of a particle in a potential box, are quantized.
3.(a) Explain the following:
i. electrical conductivity and
ii. Fermi energy.
(b) Explain briefly the classical free electron theory of metals.
(c) On the basis of band theory how the crystalline solids are classified into metals,
semiconductors and insulators?
4. (a) Describe the various processes of electric polarization.
(b) A capacitor uses aluminium oxide as the dielectric with relative permittivity
of 8. An effective surface area of 360 sq.cm. gives a capacitance of 6µF.
Calculate the field strength and the total dipole moment induced in the oxide
layer if a potential difference of 15 V exists across the capacitor. [permittivity
of free space = 8.85 ×10-12 F/m]
5. (a) What is meant by superconductivity?
(b) What are Type-I and Type-II superconductors?
(c) Calculate the critical magnetic field of a superconductor at 4.2 K. Given that
the critical temperature of the material is 7.18 K and the critical magnetic
field at 0 K is 6.5 × 104 amp/m.
6. (a) Explain the terms which are related to lasers: i. absorption
ii. spontaneous emission
iii. stimulated emission
iv. population inversion
v. pumping mechanism and
vi. optical cavity
(b) Write any four applications of laser.
7.(a) Distinguish between light propagation in (i) step index and (ii) graded index
optical fibers.
(b) Discuss the various advantages of communication with optical fibers over the
conventional coaxial cables.
(c) Calculate the refractive indices of core and cladding of an optical fiber with a
numerical aperture of 0.33 and their fractional difference of refractive indices
being 0.02.
8. (a) Write a detailed note on nanoscience.
(b) Why nanomaterials exhibit different properties? Explain.
|