Jawaharlal Nehru Technological University Hyderabad 2005 B.E Computer Science applies physics - Question Paper

I B. Tech Supplementary Examinations, June 2005
APPLIED PHYSICS


Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks

1. (a) discuss photoelectric effect and derive an expression for photoelectric current
density using FermiDivac
statistics in metals?
(b) State and write the relevance of Blochs theorem for the electron in periodic
lattice.
2. (a) explain various sources of polarizability and find an expression for
orientation polarizability subsequent Boltzman statistics.
(b) compute the polarizabiltiy of Argon atom if it’s relative permittivity at
O 0 C and 1 atoms pressure is 1.0004.
3. (a) discuss how quantum theory of Para magnetism leads to the statement that
susceptibility varies inversely with temperature.
(b) compute the relative permeability of a paramagnetic material with 3500
amp.m1
magnetization and 0.05 web.m-2 flux density.
4. (a) Prove that the position of Fermi level with reference to intrinsic level deter
mines a semiconductor whether it is Ptype
a ntype.
(b) explain the ‘Law of Mass Action’ in semiconductors.
5. (a) explain the mechanism of ‘Drift and Diffusion’ in semiconductors and derive
Continuity equations.
(b) Briefly discuss ‘Quasi Fermi Levels’.
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Earning:   Approval pending.