Q.1
If NaCl is doped with 10–3 mol % of SrClwhat is the concentration of cation vacancies?
  • 6.02 x 10 23
  • 6.02 x 10 20
  • 6.02 x 10 18
  • 6.02 x 10 19
Q.2
A cubic solid is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-centre. What is the formula of the compound?
  • PQ
  • P2Q
  • PQ2
  • PQ4
Q.3
The total number of tetrahedral voids and octahedral voids per unit cell of face-centred cell (fcc) are
  • 8, 4
  • 4, 8
  • 2, 4
  • 4, 2
Q.4
Niobium crystallises in body-centred cubic structure. If density is 8.g cm–calculate atomic radius of niobium using its atomic massu.
  • 331 pm
  • 143 pm
  • 331 nm
  • 143 nm
Q.5
Iron oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by iron ions. What is the formula of the iron oxide?
  • FeO
  • Fe2O3
  • Fe3O4
  • None of these
Q.6
On doping Ge metal with a little of In(Indium) we get
  • n - type semiconductor
  • p-type semiconductor
  • insulator
  • rectifier
Q.7
When electrons are trapped in the crystal in the anionic vacancy, the defect is known as
  • Schottky defect
  • Frenkel defect
  • Stoichiometric defect
  • F-centre
Q.8
Schottky defect is observed when
  • unequal number of cations and anions is missing from the crystal lattice.
  • equal number of cations and anions is missing from the crystal lattice.
  • an ion leaves its normal site and occupy interstitial site.
  • density of the crystal increases.
Q.9
Inclose packing the ABCABCABC.....pattern gives rise to which type of close packing?
  • Hexagonal Close Packing (hcp)
  • Cubic Close Packing (ccp)
  • Face Centred Cubic Packing (fcc)
  • Both ccp and fcc
Q.10
The number of atoms per unit cell in simple, fcc and bcc unit cells are
  • 1, 4, 2
  • 1, 2, 4
  • 2, 1, 4
  • 2, 4, 1
0 h : 0 m : 1 s