Bangalore University 2006-2nd Sem B.E Engineering Physics First /BE , - Question Paper

NEW SCHEME
First / 2nd Semester B. E. Degree Examination, July 2006
Common to All Branches
Engineering Physics
Time: three Hrs.] [Max. Marks: 100

Note: 1. ans any 5 full ques..
Electron mass=m=9.11 x 10-31 kg, Electron charge=e=1.6x10-19 C, Velocity of light=C=3x108 m/s
Planck’s constant=h=6.63x10-34 J-S, Permittivity of vacuum = ?o=8.85 x 10-12 F/m,
Avogadro’s Number = NA=6.025x10226 /K.mole, Boltzman
Constant=K=1.38x10-23J/K

1. a. State de-Brogle hypothesis and derive an expression for de-Broglie wavelength using the concept of group velocity. (06 Marks)
b. discuss and deduce the expression for phase velocity and group velocity. Derive the relation ranging from them. (10 Marks)
c. compute the de-Broglie wavelength associated with 400gm cricket ball with a speed of 90 Km/hr. (04 Marks)

2. a. obtain Eigen valves and Eigen functions for a particle in 1 dimensional potential well of finite width and infinite height. A quantum particle confined to 1 dimensional potential well of finite width is known to be in its 1st excited state. What is the probability that the particle will be anywhere in the central half of the box? (12 Marks)
b. discuss the BSC theory of superconductivity. (04 Marks)
c. discuss the working of SQUID. (04 Marks)

3.a. Elucidate the difference ranging from classical free electron theory and quantum free electron theory. define how quantum free electron theory has been successful in overcoming the failures of classical free electron theory.
(09 Marks)
b. describe Fermi factor and hecne explain the probability of occupation of different energy states by electrons at T=0K and T>0K (07
c. compute the probability of an electron occupying an energy level 0.02 eV above the Fermi level at 200K and 400K in a material. (04 Marks)

4. a. discuss the basic principles involved in laser action. (06 Marks)
b. describe electric polarization and static dielectric constant of materials and derive a relationb etween them. If a NaCl crystal is subjected to an electric field of 1000 V/m and the resulting polarization if 4.3 x 10 –8 calcualte the static dielectric constant of NaCl. (10 Marks)
c. What is dielectric loss? Derive an expression for dielectric loss. (05 Marks)

5. a. discuss the basic principles involved in Laser action. (06 Marks)
b. define the construction and working principle of He-Ne gas laser.
(08 Marks)
c. discuss ‘Holography’ principle and mention its applications. (06 Marks)

6. a. With a neat diagram derive an expression for numerical aperture and condition for propagation in optical fiber. (08 Marks)
b. the attenuation of light in an optical-fiber is estimated as 2.2 dB/km. What fractional initial intensity remains after 2kms and 6kms? (04 Marks)
c. define the construction and working of Bragg’s X-ray spectrometer and how it is used to determine the wave length of X-rays. (08 Marks)

7. a. discuss Miller indices. How to compute packing fraction for bcc structure. 08 Marks)
b. Draw the subsequent planes in a cubic unit cell [132], [110], [010], [121].
(08 Marks)
c. With a neat figure define the structure of NaCl. (04 Marks)

8. a. discuss the advantages and disadvantages of composite materials
(06 Marks)
b. discuss the basic principles of quantum calculation. (06 Marks)
c. elaborate smart materials? discuss the properties of smart materials.
(08 Marks)

Earning:   Approval pending.