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

AgBr(s) crystals shows the following defect/s 

I. Schottky defect

II. Frenkel defect

III. Metal excess defect

IV Metal deficiency defect

1.  I and II

2.  III and IV

3.  I and III

4.  II and IV

The most efficient packing is present in -

1. HCP and BCC

2. HCP and CCP

3. BCC and CCP

4. BCC and Simple cubic cell

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

1.  74

2.  68

3.  32

4.  26

The incorrect statement among the following regarding hexagonal close packing is: