# Resistivity

on . Posted in Electrical Engineering

Resistivity, abbreviated as $$\rho$$, is a property of materials that describes their inherent resistance to the flow of electric current.  It is a measure of how strongly a material opposes the flow of electrical current through it.  The resistivity of a material depends on various factors such as its composition, temperature, and physical structure.

Materials with high resistivity impede the flow of current more effectively than those with low resistivity.  For example, insulators like rubber have high resistivity, while conductors like copper have low resistivity.  Resistivity plays a role in various electrical applications, including designing electronic circuits, determining the efficiency of electrical transmission lines, and selecting suitable materials for specific purposes.

### Resistivity formula

$$\rho \;=\; R \; A_c \;/\; l$$     (Resistivity)

$$R \;=\; \rho \; l \;/\; A_c$$

$$A_c \;=\; \rho \; l \;/\; R$$

$$l \;=\; \rho \; A_c \;/\; R$$

Symbol English Metric
$$\rho$$ (Greek symbol rho) = resistivity - $$ohm-m$$
$$R$$ = electric resistance of the material $$\Omega$$ $$kg-m^2\;/\;s^3-A^2$$
$$A_c$$ = area cross-section of the material through which the current flows $$ft^2$$ $$m^2$$
$$l$$ = length of the material through which the current flows $$in$$ $$mm$$

Tags: Electrical Current