A ferromagnetic substance becomes a permanent magnet when it is placed in a magnetic field because:

1.	All the domains get oriented in the direction of the magnetic field.
2.	All the domains get oriented in the direction opposite to the direction of the magnetic field.
3.	Domains get oriented randomly.
4.	Domains are not affected by the magnetic field.

The correct order of the packing efficiency in different types of unit cells is-

1.  Fcc < Bcc < Simple cubic

2.  Fcc > Bcc > Simple cubic

3.  Fcc < Bcc > Simple cubic

4.  Bcc < Fcc > Simple cubic

Dislocation defect is also known as-

1. Frenkel defect.

2. Schottky defect.

3. Non-stoichiometric defect.

4. Simple interstitial defect.

The edge lengths of the unit cells in terms of the radius of spheres constituting fcc, bcc, and simple cubic unit cells are respectively -

1. $2\sqrt{2\mathrm{r}}, \frac{4\mathrm{r}}{\sqrt{3}}, 2\mathrm{r}$

2. $\frac{4\mathrm{r}}{\sqrt{3}}, 2\sqrt{2\mathrm{r}}, 2\mathrm{r}$

3. $2\mathrm{r}, 2\sqrt{2\mathrm{r}}, \frac{4\mathrm{r}}{\sqrt{3}}$

4. $2\mathrm{r}, \frac{4\mathrm{r}}{\sqrt{3}}, 2\sqrt{2\mathrm{r}}$

Correct statement among the following regarding conductivity in solids is -

1.   ${\mathrm{\kappa }}_{\mathrm{metals}} \gg {\mathrm{\kappa }}_{\mathrm{insulators}} < {\mathrm{\kappa }}_{\mathrm{semiconductors}}$

2.   ${\mathrm{\kappa }}_{\mathrm{metals}} \ll {\mathrm{\kappa }}_{\mathrm{insulators}} < {\mathrm{\kappa }}_{\mathrm{semiconductors}}$

3.   ${\mathrm{\kappa }}_{\mathrm{metals}} , {\mathrm{\kappa }}_{\mathrm{semiconductors}} > {\mathrm{\kappa }}_{\mathrm{insulators}} = \mathrm{zero}$

4.  ${\mathrm{\kappa }}_{\mathrm{metals}} < {\mathrm{\kappa }}_{\mathrm{semiconductors}} > {\mathrm{\kappa }}_{\mathrm{insulators}} \ne \mathrm{zero}$

Consider the following statements about semiconductors.

1. I and II

2. II and III

3. III and IV

4. I and IV

Match the defects given in Column I with the statements given in Column II.

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Match the types of defects given in Column I with the statement given in Column II.

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Match the items given in Column I with the items given in Column II.

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Match the type of packing given in Column I with the items given in Column II.

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