Consider the following statements about semiconductors.

1. I and II

2. II and III

3. III and IV

4. I and IV

The electrical conductivity of semiconductors increases with a rise in temperature because:

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

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

The incorrect statement among the following is:

The phenomenon in which polar crystals on heating produce electricity is called:-

1. Pyro-electricity.
2. Piezo-electricity.
3. Ferro-electricity.
4. Ferri-electricity.

The magnetic substances that have lesser magnetic moment than expected is known as -

1. Paramagnetic.

2. Ferrimagnetic.

3. Antiferromagnetic.

4. None of the above.

Select the correct option based on statements below: