Difference between resistance and resistivity

Resistance vs resistivity: an overview 

One of the major differences between the resistance and the resistivity of any material is that resistance is the property that opposes the flow of free electrons. On the other hand, resistivity is the property of the material which defines the resistance of the material while having precise dimension. 

Basic differences among resistance and resistivity

Some of the major differences between these two terms give below: 

Definition

Resistance is the possession of any substance due to which it opposes the smooth flow of electrons. Simple words, it can define as an opposite force. In contrast, we define resistivity as the resistance of material having precise proportions. Hence, In the simplest words, it is an electrical resistance of a conductor of unit cross-sectional area and unit length. Therefore, It considers a characteristic property of each material and is very useful in comparing materials based on their capability to conduct electric currents. 

Formula 

The formula of resistance and resistivity is quite different from one another as both of them yield different outcomes. 

• Formula for resistance: R = p (l / a)
• Formula for resistivity: p = (r x a) / l

SI units

The SI units are commonly used to measure these properties and are considered as a standardized system of measurement. 

• SI Unit of resistance: Ohms
• SI unit of resistivity: Ohms-meter

Symbol

Resistance is represented by “R” whereas resistivity is represented by “ρ”

Dependence

Resistance is dependent on Length, the cross-section area of the conductor, and temperature. Whereas the resistivity is dependent on Temperature only. 

Nature of resistance and resistivity 

Hence, Some of the basic differences like both properties are given below: 

Resistance

The resistance creates an obstacle in the flow of the current. Whenever the voltage will apply across the conductor, the free electrons will start moving in a precise direction. During their motion, they will collapse with atoms or molecules and therefore produce heat. These atoms or molecules will oppose the free motion of electrons in that material. This opposition takes place due to resistance. It can calculate by applying the formula: R = p (l / a)

• Where l is representing the length of the conductor
• a denotes the cross-section area of the conductor
• ρ is the resistivity of the material.

The resistance of any material rest on the following factors: 

• The resistance of the wire will always increase with the increase in the length of the conductor.
• It will be inversely proportional to the cross-section area of the conductor.
• Resistance will be dependent on the material and temperature of the wire. Therefore, it will keep on changing with the increase or decrease in temperature. 

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Resistivity

The resistivity is commonly papular as specific resistance. It is the resistance of the material which possesses some specific dimensions, for example, the wire has a 1-meter length and its cross-sectional area is 1 square meter.  It is usually represented by p = (r x a) / l.

• Where l represents the length of the wire
• a is cross-section area 
• R denotes the Resistance