The incorrect statement among the following regarding crystalline solid is -

1.	Definite and characteristic heat of fusion.
2.	Isotropic nature.
3.	A regular periodically repeated pattern of arrangement of constituent particles in the entire crystal.
4.	A true solid.

An example of amorphous solid among the following is -

1. Graphite (C)

2. Quartz glass (SiO₂)

3. Chrome alum

4. Silicon carbide (SiC)

Which of the following arrangements shows the schematic alignment of magnetic moments of antiferromagnetic substances? 

1. $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$

2. $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$

3. $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$

4. $\overline{)\uparrow }$ $\overline{)\downarrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$

Incorrect statement among the following about amorphous solids is -

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

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