1. Attempt any five parts:

List all the symmetry elements of methane molecule.

Obtain the Miller indices of the plane intersecting the three axes along the basis vectors at 2 and 4. Calculate the interplanar distance·for this plane in terms of lattice constant, a.

Arrange the following bonds in ascending order of. their strength and write one example of each:

Ionic bond

Van der Waals bond

Covalent bond

The angular frequency of a longitudinal wave propagating in a 1-D monatomic chain is 36k/n. Calculate the group velocity and It phase velocity.

Depict the energy variation of Fermi function of electrons. Prove that at E the occupation probability is 0·5.

What is the effect of dopant concentration on . the .Fermi energy of n-and p-type semiconductors?

Plot a typical hysteresis loop and write the characteristics of the hysteresis loop of the magnetic material used in high frequency applications.

Differentiate between the piezoelectric and pyroelectric crystals.

2. Attempt any two parts:

Define the atomic packing fraction. Calculate the atomic packing fraction of face centred cubic system.

Obtain the reciprocal lattice vectors for the lattice with primitive translation vectors:

a1 a2 =2j and a3 2j 2k

Explain the experimental arrangement for Laue method of X-ray diffraction. Why is it not possible to determine the lattice constant using this method

3. Attempt anyone part:

Under deformation stress, the orthogonal axes in elastic solids get deformed due to strain. Show that the deformed coordinate axes are not orthogonal.

Debye temperature of aluminium is 418 K. Calculate the maximum frequency of lattice vibrations and the thermal energy for 1 mole of AI at Debye temperature on the basis of classical heat capacity.

4. Attempt any two parts:

The lattice constant of a 2-D square lattice is 3A°. Calculate the momentum of an electron whose wave terminates at the boundary of first Brillouin zone. Then calculate its energy in eV.

Starting with the expressions for the intrinsic electron concentration and intrinsic hole concentration for a semiconductor, obtain the expression for intrinsic Fermi energy at temperature T in terms of energy gap, and effective masses of holes and electrons.

Write down important features of the crystal structure of copper oxide based high Tc superconductors. Discuss the role of Cu planes in superconductivity.

5. Attempt any two parts:

Depict the five types of point defects in a crystal.

What is a liquid crystal Explain the working of liquid crystal display.

How is a polymer capacitor used as a humidity transducer?