306) To get a n-type semiconductor from silicon, it should be doped with a substance with valence .

307) The Total number of tetrahedral voids in the face centred unit cell is ____________.

308) Which of the following point defects are shown by AgBr(s) crystals?
(A) Schottky defect
(B) Frenkel defect
(C) Metal excess defect
(D) Metal deficiency defect

309) In which pair most efficient packing is present?

310) The percentage of empty space in a body centred cubic arrangement is _______________.