## 13 May 2019

### Difference between resistance and resistivity

Resistance and resistivity are both concepts for electrical engineering. Resistance gives the ratio of potential difference to current across a conductor at a given time, whereas resistivity is the ratio of an electric field to current density for a material at a specific temperature. Here this post gives the difference between resistance and resistivity to better understand this topic.

Definition:

Resistance: Resistance is the physical property of a substance because of which it processes the flow of current.  Example - electrons
Resistivity: Resistivity is the physical property of a particular substance which is having particular dimensions.

The basic key difference between resistance and resistivity are given below:
• Resistance is directly proportional to the length and temperature while it is inversely proportional to the cross-sectional area of the material while resistivity is only proportional to the nature and temperature of the particular material.
• The symbol of resistance of  R, while the symbol of resistivity of ρ.
• The SI unit of resistance in Ohms, The SI unit of resistivity is ohms-meter.
• The resistance is the property of the material which obstructs the flow of current, whereas the resistivity gives the resistance of the material which has a fixed dimension.
• The resistance of the conductor depends on its length and area of cross sections, The resistivity of the conductor does not depend on its length and area of cross-section. It depends on the nature and temperature of the material
• The property of resistance is used in several places like heaters, fuses, sensors, etc, Electrical resistivity measurement is used as a quality control test for calcareous soil.
• R=V/I or R = ρ (L/A),  ρ = (R*A) / L . V=Voltage, I=Current, ρ=Resistivity, A= Cross sectional area, L=Lengh, R = Resistance.