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Home > Articles > SI Unit of Conductivity - Definition, Resistivity, Other Unit, Formula, and Examples
Updated on 18th April, 2023 , 5 min read
Conductivity is a fundamental property of materials that describes their ability to conduct electric current. It is an essential parameter used in various fields, including physics, materials science, chemistry, and engineering, to characterize and analyze the electrical properties of conductive materials. In this article, we will explore the SI unit of conductivity, its definition, calculation, and importance in electrical measurements.
Conductivity (σ) is a measure of how easily a material allows the flow of electric charge. It is defined as the reciprocal of resistivity (ρ), which is the inherent property of a material that opposes the flow of electric current. Mathematically, conductivity is given by the equation:
σ = 1/ρ
where σ is the conductivity and ρ is the resistivity.
The SI unit of conductivity is siemens per meter (S/m). It is named after the German physicist Ernst Werner von Siemens, who made significant contributions to the field of electrical engineering. The symbol "S" represents Siemens, and "m" represents meter, which is the unit of length in the International System of Units (SI).
Conductivity can be calculated from resistivity using the formula:
σ = 1/ρ
where σ is the conductivity in S/m and ρ is the resistivity in ohm-meters (Ω·m). This relationship indicates that materials with higher resistivity have lower conductivity, and vice versa. Conductivity is a measure of how easily a material allows the flow of electric charge, and higher conductivity values indicate better conductive properties.
The SI unit of conductivity is widely used in various electrical measurements and applications due to its importance in characterizing the electrical properties of materials. Some of the key reasons why the SI unit of conductivity is significant in electrical measurements are:
The table below shows the relativity of different materials:
Material |
Resistivity |
|
Conductor |
silver Copper Aluminium Tungsten iron Lead Mercury |
1.59 x 10-8 1.68 x 10-8 2.65 x 10-8 5.6 x 10-8 9.71 x 10 -8 22 x 10-8 98 x 10-8 |
Alloys |
Constantan (cu+Ni) Manganin (Cu + Ni + Mn) Nichrome (Ni + Cr + Mn + Fe) |
49 x 10-8 48.2 x 10-8 100 x 10-8 |
Insulators |
Glass Hard Rubber |
1 – 10000 x 109 1-100 x 1013 |
Resistors are used in circuits to control the flow of current. It is made up of several color codes. The different colors on the resistor represent the different resistance values.
ρ = E/J
Where,
ρ = the resistivity of the material
E = the intensity of the magnetic field
J = the intensity of the current density
Resistivity (ρ) = R A/l
R = electrical resistance of the regular cross-section
A = area of the cross-section
L = the length of the piece
V = W/Q
Where,
V = potential difference between two points in an electric circuit
W= work done
Q= charge
P = VI
Where,
P= electric power or the rate at which energy is consumed in the electric circuit
V= potential difference
I= current
Where,
R = Resistance which is constant at a given temperature
SI Unit of Resistance and Ohm's Law
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By - Nikita Parmar 2024-09-06 10:59:22 , 6 min readThe SI unit of electrical conductivity is Siemens per meter (S/m).
Electrical conductivity is a measure of how well a material conducts electric current. It quantifies the ability of a material to allow the flow of electric charge through it.
Electrical conductivity is typically calculated by measuring the current passing through a material under a known electric field and using the formula σ = I/(A × L), where σ is the conductivity, I is the current, A is the cross-sectional area, and L is the length of the material.
Electrical conductivity is a crucial property in various fields, such as electronics, materials science, and electrical engineering. It is used to characterize and select materials for specific applications, design electrical circuits, and analyze the behavior of conductive materials in electric fields.
Resistivity is the reciprocal of electrical conductivity and is a measure of how strongly a material opposes the flow of electric current. While electrical conductivity quantifies the ability of a material to conduct current, resistivity quantifies the resistance offered by a material to the flow of electric charge.
Electrical conductivity is always a positive value, as it represents the ability of a material to conduct electric current. Negative or zero values of conductivity would not have physical significance in most cases.
Electrical conductivity can also be expressed in other units, such as Siemens per centimeter (S/cm) or Siemens per inch (S/in), depending on the specific application or context.
Electrical conductivity of most materials generally decreases with increasing temperature, as higher temperatures can disrupt the structure of the material and reduce the mobility of charge carriers.
Yes, electrical conductivity can change for a material based on various factors, such as temperature, impurities, and mechanical stress. For example, doping a semiconductor with certain impurities can significantly alter its electrical conductivity.
Yes, electrical conductivity can be measured experimentally using various methods, such as four-point probe technique, two-point probe technique, or Hall effect measurements. These methods involve applying an electric field, measuring current and voltage, and using appropriate equations to calculate electrical conductivity.