Conductivity

Conductivity, abbreviated as \( \gamma \) (Greek symbol gamma) and \( \sigma \) (Greek symbol sigma), also known as electrical conductivity or specific conductance, is a property that measures a material's ability to conduct an electric current.  Electric conductivity is determined by the presence of charged particles, such as electrons or ions, that are free to move within the material.  When an electric potential difference (voltage) is applied across a material, the charged particles can flow, creating an electric current.  Materials with high conductivity allow for the easy flow of electric current, while materials with low conductivity impede or restrict the flow of current.

Different materials have varying degrees of conductivity.  Metals, such as copper, silver, and aluminum, are excellent conductors of electricity due to their high concentration of free electrons that can move easily through the material.  They have high electrical conductivity values.  On the other hand, insulators, such as rubber, glass, or plastic, have very low conductivity and hinder the flow of electric current.  Insulating materials have their electrons tightly bound and are not easily free to move.

Semi-conductors, like silicon and germanium, exhibit intermediate levels of conductivity.  Their conductivity can be modified by introducing impurities or by applying external factors such as temperature or light.  This property makes them valuable in electronic devices like transistors and integrated circuits.

Conductivity finds extensive use in various applications, including electrical and electronic engineering, material science, and environmental monitoring.  It is used to determine the suitability of materials for electrical conductors, to assess the quality of water or other liquids, and to design and analyze electrical circuits and systems.  The conductivity of a material can be influenced by factors such as temperature, impurities, moisture content, and the presence of magnetic fields.  Therefore, it's important to consider these factors when evaluating or working with conductive materials.

 

Conductivity formula
\( \gamma  =  I \;/\; R \)     (Conductivity) \( I  =  \gamma \; R \) \( R  =  I \;/\; \gamma \)
Symbol	English	Metric
\( \gamma \) (Greek symbol gamma) = conductivity	-	\(S\;/\;m\)
\( I \) = electric current	\(I\)	\(C\;/\;s\)
\( R \) = electric resistance	\(\Omega\)	\(kg-m^2\;/\;s^3-A^2\)

 

Conductivity Formula
\( \gamma =   J \;/\; E \)     (Conductivity) \( J =  \gamma \; E  \) \( E =   J \;/\; \gamma \)
Symbol	English	Metric
\( \gamma \) (Greek symbol gamma) = conductivity	-	\(S\;/\;m\)
\( J \) = electric current density	-	\(A\;/\;m^2\)
\( E \) = electric field	-	\(V\;/\;m\)