Difference Between Resistance and Resistivity

Main Difference

The main difference between resistance and resistivity is that resistance opposes the flow of current and free electrons, whereas the resistivity describes the resistance of the specific material having a particular dimension.

Resistance vs. Resistivity

Resistance is a specific property of a material that creates obstacles in the flow of current; conversely, resistivity is a particular resistance having the specific dimensions. Resistance in a conductor is generally the ratio of the potential difference of the current passing through it, while resistivity is usually the ratio of electric field strength to the current density present at a particular temperature. The unit of resistance is measured by ohms (Ω), whereas the unit of resistivity is generally measured in ohmmeters (Ω m). The symbol of resistance is R; on the contrary, the symbol of resistivity is ρ.

Resistance is considered as a property of a specific object and be determined by the temperature, object’s material, along with its dimensions (directly proportionate to length, inversely related to the cross-sectional part in a constant metal wire); on the other hand, resistivity is usually a property of a specific material, and it is independent on the dimensions, but it is, though, reliant on temperature and the material of the conductor. The formula for resistance is written as R = V/I or R = ρ(L/A); on the flip side, the formula for resistivity is written as ρ = (R×A)/L.

The applications of the property of resistance in daily life are used in various places and things like fuses, heaters, sensors, etc.; on the other hand, the applications of electrical resistivity measurement are involved in calcareous soil and a quality control test. Resistance is always connected to the specific conductor; on the flip side, resistivity is usually linked with the material of the conductor.

Comparison Chart

ResistanceResistivity
The property of a substance that offers opposition to the flow of current is known as resistance.The resistivity of 1m3 of a substance is equal to specific resistance.
Ratio Of
The ratio of potential difference through it to the current passingThe ratio of electric field strength to the current density present at a particular temperature
Unit
The unit of resistance is ohms (Ω)The unit of resistivity is ohm meters (Ω m)
Symbols
The symbol of resistance is RThe symbol of resistivity is ρ
Considered As
Considered as a property of a specific object and be determined by the temperature, object’s material, along with its dimensionsUsually a property of a specific material
Temperature Dependency
Depends on temperatureDepends on temperature and the material of the conductor
Dimensional Dependency
Depends on dimensionDoes not depend on the dimension
Length and Cross-Sectional Area Dependency
Directly proportionate to length, inversely related to the cross-sectional part in a constant metal wireDoes not depends on the length and cross-sectional area of the conductor
Formula
R = V/I or R = ρ(L/A)ρ = (R×A)/L
Connection with Conductor
Always connected to the specific conductorUsually linked with the material of the conductor
Applications
The applications of the property of resistance in daily life are used in various places and things like fuses, heaters, sensors, etcThe applications of electrical resistivity measurement are involved in calcareous soil and a quality control test

What is Resistance?

The term resistance is used in conductors and acts as an obstacle in the flow of current or free electrons that are present in a conductor. Resistance (R) in a conductor is generally the ratio of potential difference (V) of the current (I) passing through it. It is mathematically written as R = V/I or R = ρ(L/A).

Where, l – length of the conductor, a – cross-section area of the conductor, ρ – resistivity of the material. When the flow of charges occurs in a conductor, the flow of electric current starts to travel. When a current is flowing over a wire, it looks like water flowing in a water pipe, and when the voltage descent in the wire it is similar to the decrease of pressure that drives water in the pipe.

For example, let’s consider a flow of electric current in a uniform piece of cylindrical wire as a result of potential difference. When this flow of electrons in an electric wire happens, the atoms present in wire vibrate their nuclei and very repeatedly hit the electrons off from their flowing path and produce heat and this opposition results in the occurrence of resistance. The lengthier the cylinder, the extra collisions of charges will occur with its atoms.

The unit of resistance is measured by ohms, and it is generally represented by Ω at kΩ. The resistance is directly proportional to the diameter, so the bigger the width of the cylinder, the greater the current it can take. Different materials have different resistance for the movement of charge in the conductor.

The direction of the current is nominated by I sideways with a symbol of the arrow and usually flow with the flow of positive charge and flow opposite to the flow of negative charges. So it means the resistance is present where the current is flowing in the conductor in the direction of positive charges. The applications of the property of resistance in daily life are used in various places and things like fuses, heaters, sensors, etc.

Resistance across a metal wire is directly proportional to the length and inversely related to the cross-sectional part in a constant metal wire.

Factors Affecting Resistance

  • The resistance of the wire generally increases with the increase in the length of the conductor.
  • Resistance is inversely proportionate to the cross-section area of the metal conductor.
  • Resistance rest on the material of the wire.
  • The resistance of the material usually depends on its temperature.
  • Small wires usually consist of minor resistance; big wires consist of huge resistance.
  • Various materials develop superconductors when these materials decrease below a critical temperature which offers zero resistance to the flow of current in the conductor.

What is Resistivity?

The term resistivity is a particular resistance having specific dimensions. The two particular situations and when associate, they form an equation of resistivity which is as ρ = (R×A)/L

Where ρ is the constant (known as the Greek letter “rho”) called resistivity of the material, l – length of the conductor, a – cross-section area of the conductor, and R – Resistance of the material. Resistivity is usually a property of a specific material, and it is independent of the dimensions, but it is, though, reliant on temperature and the material of the conductor.

Resistivity is usually the ratio of electric filed (E) strength to the current density (J) present at a particular temperature written as ρ = E/J. The unit of resistivity is generally measured in ohmmeters (Ω m) and R symbolizes it. The resistivity across a metal wire is directly proportionate to the temperature of the material, and it is independent of the dimensions.

Factors affecting resistivity are included as the resistivity of a conductor rises with an increase in its temperature, and the resistivity of a conductor decreases with a decrease in temperature. Some applications of resistivity are used in calcareous soil and a quality control test.

Key Differences

  1. A property that creates obstacles in the flow of free electrons and current is usually the resistance; conversely, a particular resistance having the specific dimensions is given by resistivity.
  2. Resistance is linked to the specific conductor; on the flip side, resistivity is connected with the material of the conductor.
  3. In a conductor, the resistance is the ratio of potential difference through which the current passing, while resistivity is usually the ratio of electric field strength to the current density happening at a specific temperature.
  4. The unit of resistance is ohms (Ω), whereas the unit f resistivity is commonly the ohmmeters (Ω m).
  5. The symbol of resistance is R; on the contrary, the symbol of resistivity is ρ.
  6. Resistance is directly proportionate to the length and inversely related to the cross-sectional part in a constant metal wire; on the other hand, resistivity depends on the temperature of the metal wire, but it is independent of the dimensions.
  7. Resistance is determined by the temperature, object’s material, along with its dimensions and it is considered as a property of a specific object; on the contrary, resistivity is normally a specific property of a specific material.
  8. The formula for resistance is written as R = V/I or R = ρ(L/A); on the flip side, the formula for resistivity is written as ρ = (R×A)/L.
  9. The applications of resistance in daily life is that it is used in various places and things like fuses, heaters, sensors, etc.; on the other hand, the applications of electrical resistivity are that it is involved in calcareous soil and a quality control test.

Conclusion

The above discussion concludes that the resistance opposes the flow of current and free electrons and it is directly dependent on the dimension and cross-section of area or length, whereas the resistivity is the resistance of the specific material having a particular dimension but independent of the dimension, reliant on temperature.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss

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