Iodine molecules are held in the crystals lattice by ........ .

1.  London forces.

2.  Dipole-dipole interactions.

3.  Covalent bonds.

4.  Coulombic forces.

 

Network solid, among the following, is :

1. SO₂(solid)

2. I₂

3. Diamond

4. H₂O(ice)

I. Mg(s)

II. TiO(s)

III. I₂(s)

IV. H₂O(s)

The insulator among the given examples is -

1. Only I

2. Only II

3. III and IV

4. II, III, and IV

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.

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:

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