Jawaharlal Nehru Technological University Hyderabad 2005 B.E Computer Science APPLIED PHYSICS I BTech Supplementary s, (For 2000 batch only) - Question Paper

Code No: NR10251 NR
I B.Tech Supplementary Examinations, June 2005
APPLIED PHYSICS
(For 2000 batch only)
(Electrical & Electronic Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
? ? ? ? ?
1. (a) discuss the subsequent terms relating to motion of free electrons:
i. relaxation time,
ii. collision time and
iii. mean free path[8+8]
(b) define the ‘free electron model’ of a metal, introduced by Summerfield.
2. (a) explain with suitable mathematical expressions, the motion of an electron in
a periodic potential.
(b) How the above theory leads to the concepts of band structure of solids and
Brillouin Zones?[8+8]
3. (a) What is meant by polarization of a dielectric material? Mention the various
mechanisms of polarization in a dielectric.
(b) Write notes on ferroelectricity.[8+8]
4. (a) discuss briefly Langevin theory of Para magnetism and Weiss theory of Ferromagnetism.
(b) Derive an expression for the change in the angular velocity of an electron in
an atom of a diamagnetic substance when it is subjected to an external magnetic
field and hence discuss the origin of diamagnetism.[8+8]
5. (a) discuss the characteristics of a laser beam.[8+8]
(b) define the construction and working of a semiconductor laser.
6. (a) How are ‘superconductors’ classified? discuss their properties.
(b) Write notes on the applications of superconducting materials.[8+8]
7. (a) provide the theory of direct recombination of carriers in semiconductors.
(b) find the expression for the decay of minority carriers injected into a semiconductor[8+8]
8. Write short notes on the following:
(a) IC fabrication
(b) Hall effect
(c) Photodiodes
(d) Effective mass[4+4+4+4]]

Earning:   Approval pending.