Resistance is simply the hindrance to electron flow. It is a physical property of the material that takes place due to the numerous collisions of the electron with the fixed atoms inside the conductor.
In contrast, resistivity indicates the conducting ability of the material. It increases with the increase in temperature. The lower the resistivity, the greater the conductivity of a material.
Resistance vs Resistivity
Resistance and resistivity, both terms sound alike, but they have quite different meanings in their names. We will divide the topic into subtopics to help the reader grasp a better idea of the fundamentals.
Electrical resistance implies the opposition to the current flow in an electrical circuit. It is simply a physical property of a conductor material that obstructs the flow path of the current.
The science behind is that the free electrons in the material start moving as the voltage is applied across the conductor. This allows the atoms and molecules to collapse the electrons and oppose the movement of free electrons.
Resistivity is defined as the characteristic property of a material that allows it to resist the current flowing through it. To be more precise, it is the resistance of a material having definite dimensions. This is why resistivity is also referred to as specific resistance or volume resistivity.
In a more bookish way, resistivity can be defined as the resistance offered by the material per unit length for a unit cross-section. It varies linearly with temperature. The more the resistivity, the more will be the resistance of a specific material of specific size to electrical conduction.
Resistance is represented by the formula
Where “l” is the length of the conductor, “a” is the cross-sectional area of the conductor, and “ρ” is the resistivity of the material. The SI unit of resistance is Ohms.
Therefore, it is clear that resistance increases as the length of the conductor increases and decreases with the increase of the cross-sectional area of the conductor. Not to mention, it also depends on the material and the temperature.
Resistivity varies proportionally with the temperature of the material. However, it is proportional to the cross-sectional area and inversely proportional to the length of the conductor. The SI unit of resistivity is Ohms-meter.
Resistance is a basic element in an electrical circuit. It has its applications almost everywhere whenever conduction is concerned. Having said that, the property of resistance is particularly useful in amplifiers, fuses, telecommunication, sensors, heaters, etc.
Resistivity has its prime application in converting electrical energy to heat energy. Moreover, it is used for damping purposes in mechanical systems such as braking. It is also widely applied in quality control tests such as calcareous soil tests.
Understanding the difference between resistance and resistivity is one of the most fundamental knowledge for anyone concerned with this field. Although they may seem quite the same, these two are distinct properties of a conductive material and need to be specified for certain purposes. It will help deal with more complex topics of electricity later on.