07-07-2012, 04:25 PM
EP 2 QUESTIONS
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UNIT I QUANTUM MECHANICS & QUANTUM COMPUTING
1. (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. [10+6]
2. (a) Derive the time independent Schrodinger’s equation for a free particle.
(b) Explain the significance of wave function. [ 12M + 3M ]
3. (a) Show that energies of a particle in a potential box are quantized.
(b) An electron is confined to a one dimensional potential box of length 2 Å. Calculate the energies corresponding to the second and fourth quantum states in eV.[11M + 4M]
4.(a) Derive the time dependent Schrodinger wave equation.
(b) What are qubits, multiple qubits.Explain.
5. (a) What are quantum gates. Explain.
(b) Explain the advantages of quantum computing.
UNIT II FREE ELECTRON THEORY OF METALS
1. (a) Explain the following i). electrical conductivity and (ii). Fermi energy.
(b) Explain briefly the classical free electron theory of metals.
© On the basis of band theory how the crystalline solids are classified into metals,
semiconductors and insulators? [4+6+6]
2. (a) Explain the salient features of Classical free electron theory.
(b) Derive an expression for the electrical conductivity of a material using classical free
electron theory.
© Find the relaxation time of conduction electrons in a metal of resistivity 1.54 x 10-8 m,
if the metal has 5.8 x 1028 conduction electrons per m3.[3M + 8M + 4M]
3. (a) Explain the salient features of Classical free electron theory.
(b) On the basis of classical free electron theory, derive the expressions for
(i) Drift velocity, (ii) current density and (iii) mobility.
© What are the drawbacks of classical free electron theory of metals.[3M + 9M + 3M]
4. (a) Explain the Fermi-Dirac distribution function of electrons. Illustrate graphically the effect of temperature on the distribution.
(b) Discuss the origin of electrical resistance in metals.
© Evaluate the Fermi function for an energy kT above Fermi energy.[6M + 6M + 3M]
5. (a) What is Fermi level?[2]
(b) Explain Fermi-Dirac distribution for electrons in a metal. Discuss its variation
with temperature. [8]
© Calculate the free electron concentration, mobility and drift velocity of elec-
trons in aluminum wire of length of 5 m and resistance 0.06 carrying a
current of 15 A, assuming that each aluminum atom contributes 3 free elec-
trons for conduction.
Given: Resistivity for aluminum = 2.7× 10−8 -m.
Atomic weight = 26.98
Density = 2.7 × 103 kg/ m3
Avagadro number = 6.025 × 1023 [6]