Graphite is a good conductor of electricity due to the presence of ......... .
(1) Lone pair of electrons.
(2) Free valence electrons.
(3) Cations.
(4) Anions.
Which of the following oxides behaves as a conductor or insulator depending upon temperature?
1. TiO
2. SiO2
3. TiO3
4. MgO
Which of the following oxides shows electrical properties like metals?
1. SiO2
2. MgO
3. SO2 (s)
4. CrO2
The lattice site in a pure crystal cannot be occupied by ......... .
1. Molecule
2. Ion
3. Electron
4. Atom
Graphite cannot be classified as ...........
1. Conducting solid.
2. Network solid.
3. Covalent solid.
4. Ionic solid.
Cations are present in the interstitial sites in ............ .
1. Frenkel defect.
2. Schottky defect.
3. Vacancy defect.
4. Metal deficiency defect.
Schottky defect is observed in crystals when:
1. | Some cations move from their lattice site to interstitial sites. |
2. | Equal number of cations and anions are missing from the lattice. |
3. | Some lattice sites are occupied by electrons. |
4. | Some impurities are present in the lattice. |
Chargewise p-type semiconductor is -
1. Positive.
2. Neutral.
3. Negative.
4. Depends on the concentration of p impurity.
To get a n-type semiconductor from silicon, it should be doped with a substance with valency -
1. 2
2. 1
3. 3
4. 5
The total number of tetrahedral voids in the face centered unit cell is -
1. 6
2. 8
3. 10
4. 12