Q1// Do the electrons or phonons carry the greater partof the heat current in a metal? Explain that.

Q2//Explain the origin of the energy gap and find themagnitude of the energy Gap.

Q3// Give general remarks aboutBloch^,stheorem.

Q4//    Complete the following statements:-

1. The energy of the topmost filled level in the groundstate of the (N) electron System is calledas------------------------.
2. The number of orbitals per unit energy range is calledas----------------------.

     (3)The model answers almost allthe qualitative questions about the behavior of electron in metalsis --------------------------. (4) The electrical resistivity ofmost metals is dominated at liquid helium temperature by collisionsof the conduction electrons with--------------------------- in thelattice.

(5) The crystals is called ---------------------- orsemimetal if one or two bands are slightly filled or slightlyempty.                                                         

(6)At temperatures much belowboth the Debye temperature and the Fermi temperature ,the heatcapacity of metals may be written as--------------------.                       

(7) The number of orbitals with the same energy iscalled -----------------------.

(8) At absolute zero the chemical potential is equal to---------------------------.

(9)The region which results from intraction ofconduction electron waves with the ion cores of the crystals iscalled-------------------------.