Resistance is defined as the property of the conductor which opposes the flow of electric current. It is also defined as the ratio of the voltage applied to the electric current flowing through it. The resistance of a conductor depends on the length, area of cross-section, and the nature of the material used in the conductor’s manufacturing. For a conductor, the resistance is directly proportional to the length of the conductor and inversely proportional to the area of the cross-section.
Resistivity is defined as the resistance offered by the material per unit length for a unit cross-section. The SI unit of resistivity is ohm-meter. Resistivity increases linearly with temperature. The resistivity of conductors is low compared to the insulators’ resistivity. Therefore, it can be represented as:
The resistivity of conductors < Resistivity of alloys < Resistivity of insulators.
Before moving to their differences, it is important to know what resistance and resistivity are and other related details like resistivity of various materials.
Check the table given below for the detailed comparison and differences between resistivity and resistance.
Difference Between Resistance and Resistivity
| Sl. No. | Differentiating Property | Resistance | Resistivity |
| 1 | Definition | Resistance is the physical property of a substance because of which it opposes the flow of current i.e. electrons. | Resistivity is the physical property of a particular substance which is having particular dimensions. |
| 2 | Proportionality | Resistance is directly proportional to the length and temperature while it is inversely proportional to the cross-sectional area of the material. | Resistance is only proportional to the temperature of the conductor. It also depends on the nature of the material of the conductor. |
| 3 | Symbol | R | ρ |
| 4 | Formula | R = V/I or, R = ρ(L/A) V = Voltage, I = Current, ρ = Resistivity |
ρ = (R×A)/L R = Resistance, L= Length, A = Cross-sectional area |
| 5 | SI Units | The SI unit of resistance is ohm | The SI unit of resistivity is ohm-metre. |
| 6 | Applications | 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. |
These were the main resistance and resistivity differences that are crucial to understand. Questions based on resistivity and resistance are common in most exams and so, it is important to be thorough with these comparisons.
To know more about electrical resistance and resistivity along with their formulas, visit the links given below.
| Resistivity of Materials | Electrical Resistance |
| Resistivity and Temperature Dependence of Resistivity | The Temperature Dependence of Resistance |
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