Thoretical Questions of Electronic Properties of Materials
Thoretical Questions of Electronic Properties of Materials
Thoretical Questions of Electronic Properties of Materials
Chapter 7
Dielectric Materials and Insulation
5. Why the typical relaxation peaks are broader in the dielectric constant
versus frequency curve? 7.4 608
6. Derive the expression of oriental polarizability under ac field
condition. 7.4 605
7. What is “dielectric resonance”? 7.4.1 607 page
8. What is pyro-electricity? 7.8.3 650
9. How the pressure fluctuations are compensated in a pyroelectric
radiation detector? 7.8.3 651
10. Prove that, the orientational polarization is inversely
proportional to the temperature and proportional to the square of the
permanent dipole moment. 7.11 660-662
11. For a dielectric material, if Wcap is the power dissipated per unit
capacitance, show that
𝑾𝒄𝒂𝒑 = 𝑽𝟐 𝝎 𝒕𝒂𝒏𝜹
Where the symbols bear their usual meanings. 609 Example 7.5
12. Show that, for solids the internal field ( local field) for simple
cubic lattice is given by
𝑃
𝐸𝑖 = 𝐸 + 7.1.4 593
3𝜖𝑜
Chapter 8
Magnetic Properties and Superconductivity
1. Write a brief description for giant magneto-resistance 8.12 745
2. Explain Meissner effect. 8.9 729
3. In this relation, also explain the physical distinctions between type-I
and type-II superconductors. 8.9.2 733
4. Write a brief note on the three parameters defining the limits of
superconductivity. 8.9.2 8.9.3 733-736
5. For an isotropic homogenous magnetic material show that,
𝐵 = 𝜇𝑜 (𝐻 + 𝑀) 8.1.4 692
6. Short Note:
i) Ferrimagnetic Material 8.2 699
ii) Bohr magneton 8.1.2 688
14. Find orbital magnetic moment, spin magnetic moment and total
magnetic moment for Iron (26). Assume me values are filled in the
following order, me = 0, -1, +1, -2, +2. Does iron have permanent dipole
moment? Explain No Idea
15. Show that an atom moving in its orbit represents a magnetic dipole.
Discuss the effect of applying a magnetic field on these permanent
dipoles. Correlate the effect with diamagnetism 8.11 may be
16. What are the origins of permament magnetic dipole in a material?
Why do the rare earth materials show strong magnetic properties? No
idea
17. Atomic number in a material is 15. Calculate the permanent magnetic
dipole of individual atoms in A-m2 No idea
Chapter 4
Modern Theory of Solids
1. From the knowledge of band theory of solids explain why Magnesium behaves
like a metal in spite of having filled 3s band. Also explain why Carbon behaves like
a semiconductor instead of behaving like a metal. 4.2
2. Discuss the properties of Fermi – Dirac function. Also state the limitations of
Fermi-Dirac distribution. 314 page
3. Explain how holes contribute to the charge transport process in a semiconductor.
4.3
4. Derive the effective mass expression for the particle inside a semiconductor.
Session 2009-10 8(b)
5. Short note: Brillouin Zone
6. Explain how energy band is changed with the application of voltage. 4.2
7. Explain why energy bands are overlapped with each other. 4.2
8. Define density of states. Derive an expression of three dimensional density of
states. 4.5
9. Discuss the origin of energy bands in crystal with Kronig-Penny model.
10. What is Parabolic Band Approximation?
11. State two equation of Bloch theorem. What important conclusions can be made
concerning the allowed values of k from Bloch’s equation
NB: Incomplete
Chapter 2
Electrical and Thermal Conduction in Solids
1. Why the resistivity due to impurity scattering in metals is independent
of temperature? ??
2. Why the thermal conductivity of diamond is very high whereas that of
polymer is very low? 2.6.1 152
3. Draw the necessary diagram and prove that the Hall co-efficient for
ambipolar conduction depends on both the drift mobility ratio and
concentrations of holes and electrons. 2.5 158
4. Derive an equation which will establish the relationship between the
resistivity of a pure metal and temperature of the metal. 2.2 122-124
5. Describe lattice- scattering- limited and impurity- scattering-limited
drift mobility and their temperature dependence. 2.2
6. Show that for a pure metal the resistivity is given by the following
relationship. 2.2 123
𝑚𝑒 𝑇
𝜌𝑇 = 2
𝑒 𝑛𝐶
7. What kind of materials are best for making Hall Effect devices? Why?
2.5
8. Derive a quantum mechanical expression for conductivity in metals.
From this, obtain the conductivity expression as derived from Drude’s
Model. ??
Chapter 3
Quantum Mechanics
1. The solution to Schrodinger’s equation for a particular situation is given by
2 −𝑥
𝜓 (𝑥 ) = √ . 𝑒 𝑎0
𝑎0
𝑎0
Determine the probability of finding the particle between the limits 0 ≤ 𝑥 ≤
4
2. Derive a quantum mechanical expression for conductivity in metals. From this,
obtain the conductivity expression as derived from Drude’s Model.
3. Solve Schrödinger equation for a free particle whose energy is E. what is the
uncertainty in the position of the electron and uncertainty in the momentum
of the electron?
4. Briefly describe the operating principle of Scanning Tunneling Microscope.
(STM)
5. Write Schrödinger’s equation and Eigen energy expressions for 3-D structure.
6. Show that in infinite potential well the density of states per unit volume at a
particular energy is proportional to square root of that energy.
7. A one-dimensional infinite potential well with a width of 12Å contains an
electron. If the electron drops from the second energy level to the first, what is
the wave length of a photon that might be emitted?
8. A proton attempt to penetrate a rectangular potential barrier of height 10MeV and
thickness 10−14 m. The particle has a total energy of 3MeV. Calculate the probability
that the particle will penetrate the potential barrier.
9. A photoelectric experiment indicates violet light of wavelength 420nm is the longest
wavelength radiation that can cause photoemission of electrons from a particular
photocathode
i) What is work function in eV?
ii) If a UV radiation of wavelength 300nm is incident upon the photocathode, what
will be the maximum kinetic energy of the photoemitted electrons?
NB: Incomplete