M.SC PHYSICS SOLID STATE PHYSICS AND ELECTRONIC DEVISES QUESTION PAPAERS

KARNATAKA STATE OPEN UNIVERSITY
I Semester M. Sc. Degree Examination
PHYSICS: Solid State Physics and Electronic Devices
Time: 3 Hours Max. Marks: 80
Answer all questions
1. a) State and prove Bloch theorem.
b) Distinguish between first and second Brillouin zones. (10+5)
OR
2. a) Using Kronig-Penny model, show that energy spectrum of solids consists of number
of allowed energy bands separated by forbidden gaps.
b) Discuss a method of determining Fermi surface of a metal experimentally. (10+5)
3. a) Discuss the Sommerfeld theory of free electrons
b) Write a note on Umklapp scattering. (10+5)
OR
4. a) Discuss electrical conductivity of metals at high frequency and obtain an expression
for dielectric constant.
b) What is Gudden-Pohl effect? Discuss. (10+5)
5. a) Obtain an expression for carrier concentration in an intrinsic semiconductor
b) Explain the effect of doping on Fermi level in semiconductors. (10+5)
OR
6. a) Mention different mechanisms of excitation and emission processes. Derive an
expression for intensity of temperature independent luminescence.
b) Write a brief note on Destriau effect with an example. (10+5)
7. a) Discuss the formation of space charge region in a p-n junction diode and obtain an
expression for the width of the region.
b) Find the value of applied voltage at 296 K for a p-n junction diode if I0= 35 μA/cm2
and IF=2.6 A/cm2
(10+5)
OR
8. a) With a neat diagram, discuss the construction and working of a JFET.
b) Explain the working of relaxation oscillator using UJT (10+5)
9. Answer any FOUR questions. (5 X 4 = 20)
a) Show that the reciprocal lattice of a b.c.c is f.c.c.
b) Discuss the importance of Fermi surfaces.
c) A photon of energy equal to double the rest mass energy of electron gets back scattered
by an electron. Calculate the wavelength of scattered photon.
d) Write a note on Hall Effect and its importance.
e) In an intrinsic semiconductor at temperature of 298 K the mobility of electrons and
holes are ......... respectively. Calculate its energy gap.
Given: the resistivity of the specimen =0.37Ωm.
f) Write a note on Schotky effect.
g) Obtain an expression for current, when a p-n junction is forward biased.
h) Distinguish between BJT and JFET

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