Define specific resistance of a conductor. On what factor(s) does it depend?

Specific resistance (also known as resistivity) of a conductor is a measure of the conductor's ability to resist the flow of electric current. It is denoted by the Greek letter rho (ρ) and is defined as the resistance offered by a cube of the material of side 1 meter when the current flows perpendicular to its opposite faces. Its unit is ohm-meter (Ω.m).

The specific resistance of a conductor depends on the following factors:

1. Nature of the Material: Different materials have different atomic structures and hence, different ability to resist the flow of electric current. For example, silver has a lower resistivity than iron.

2. Temperature: The resistivity of a conductor generally increases with an increase in temperature. This is because as temperature increases, the atoms of the conductor vibrate more vigorously and obstruct the flow of electrons (current) more effectively.

3. Pressure: The resistivity of a conductor also depends on pressure but in most practical cases, this effect is negligible.

4. Impurities: The presence of impurities in the conductor material can also affect its resistivity. Generally, impurities increase the resistivity of a conductor.

It's important to note that specific resistance does not depend on the dimensions (length, cross-sectional area) of the conductor.