Solid State Physics Answers

Aluminium has three valence electrons per atom, an atomic weight of 0.02698 kg mol−1,
a density of 2700kgm-3, and a conductivity of 3.54× 107 W−1m−1. Calculate the relaxation
time in Aluminium.

Show that for a square lattice in two dimensions the kinetic energy of a free electron at a
corner of the first Brillouin zone is higher than that of an electron at the midpoint of a
side face of the zone by a factor of 2.

Calculate the intrinsic carrier concentration for GaAs at 300 K, given that,
* 0.56 ; * 0.068 and 1.42
mh = me me = me Eg = eV.

Calculate the limiting value of the magnetic field for which Nb will act as a
superconductor at 4 K. Take Bac(0) as 1970 Oe and Tc for Nb to be 9.25 K.

Explain the three types of defects in crystals.

What are transducers? Explain the working principle of a peizielectric transducer.

What are ferroelectric materials? Explain with the example of BaTiO3. How are they
different from piezoelectric materials?

With the help of a diagram, explain the working of a synchrocyclotron in your own
words.

Using the semi-empirical mass formula for the binding energy of nuclei, calculate the
value of the atomic number (Z) for the most stable nucleus at a given mass number.
Calculate Z0 for A = 60. Take the values of g = 23.7 and d = 0.71 .

With the help of the binding energy curve for nuclei, explain main characteristics of
elements and the phenomenon of nuclear fusion and fission.