Condensed Matter Physics-I

(i) The co-ordination number of unlike ions in the Sodium Chloride Structure.

(a) 12

(b) 6

(c) 4

(d) 8

(ii) The Translational Vectors →t and →G of direct Lattice and reciprocal Lattice respectively are related as :

(a) →G · →t = 0

(b) →G · →t = 1

(c) →G × →t = 0

(d) →G × →t = Integer Multiple of 2π

(iii) The momentum of a phonon is

(a) hν

(b) h/k

(c) hν

(d) zero

(iv) One dimensional effective debye temperature is

(a) hν/kT

(b) h/k

(c) kT/hν

(d) kT/ℏω

(v) The range of first brillouin zone in a monoatomic lattice is

(a) -π/a < k < 2π/a

(b) -π/a < k < +π/a

(c) 0 < k < 2π/a

(d) -2π/a < k < 2π/a

Describe the structure of ZnS.

What is Bragg's Law.

Describe strain components.

Show that an isotropic crystal has only two Independent elastic constants. What is the scheme of elastic constants for an isotropic crystal in the matrix representation.

Prove that the gradient of the optical brands of the dispersion curve at the maximum frequency is zero.

Explain crystal momentum.

Explain thermal conductivity?

Derive an expression for resonance frequency of Cyclotron.

Discuss inelastic scattering of photons by phonons.

Write short notes on :

(a) NaCl structure

(b) CsCl structure

Obtain the expression of vibrational frequency for accous mode and optical mode of a diatomic lattice.

Write short notes on :

(i) Equation of state of solids

(ii) Cyclotron resonance

Explain three dimensional bravais lattice.

What is brillouin Zone of simple cubic lattice is (2π/a)³.

Give a relation between crystal lattice axes discuss it in detail.

Derive the equation of elastic constant for cubic isotropic bodies also determine the transverse wave velocity in (1, 0, 0) direction.

Explain elastic constnat for cubic isotropic bodies.

Derive an expression for the temperature at which the thermal lattice energy is equal to zero point energy in the debye-mode.