Poor Conductor of Electricity: Air

Explanation:
- Conduction of electricity refers to the flow of electric current through a material.
- Some materials allow the flow of electric current easily, while others restrict or do not allow the flow of electric current at all. These materials are known as conductors and insulators, respectively.
- In the given options, the poor conductor of electricity is "air".
- Here is why air is a poor conductor of electricity:

1. Definition of Air:
- Air is a mixture of gases that primarily consists of nitrogen (about 78%) and oxygen (about 21%). It also contains other gases in smaller quantities.
- The molecules of air are not arranged in a regular pattern like that of solids, but they are spread randomly in all directions.

2. Conductivity of Air:
- Air is a very poor conductor of electricity because it is an insulator.
- The molecules of air do not have free electrons that can move freely and carry electric charge.
- Electric current requires the movement of charged particles (electrons or ions) through a conducting material.
- In the case of air, the molecules do not have enough free electrons to facilitate the flow of electric current.

3. High Resistivity:
- The resistivity of air is very high compared to metals or other conductive materials.
- Resistivity is a property that determines how strongly a material opposes the flow of electric current.
- Air has a higher resistivity due to the absence of free electrons, which results in a higher resistance to the flow of electric current.

4. Insulating Properties:
- Due to its poor conductivity, air is widely used as an insulating material in various applications.
- It is used to insulate electrical wires, cables, and components to prevent the flow of electric current between them.
- Air gaps or insulating materials are used to separate conductive parts to avoid electrical shocks or short circuits.

Conclusion:
- In conclusion, air is a poor conductor of electricity due to its lack of free electrons and high resistivity.