What is specific resistance?
Specific resistance is defined as the resistance offered per unit length and unit cross-sectional area when the known amount of voltage is applied. The mathematical representation is as follows:
\(\rho =\frac{RA}{L}\)Where,
⍴: specific resistance
R: resistance
A: cross-sectional area
L: length of the material
Specific resistance is the reciprocal of specific conductance, which is defined as a measure of a material’s ability to conduct electricity. The symbolic representation of specific conductance is 𝛋. It may also refer to:
- Specific electric resistance
- Specific airway resistance
- Specific resistance due to friction for a mechanism transporting mass.
Material | Specific resistance at 20 °C |
Ohms | |
Silver | 9.8 |
Copper | 10.37 |
Gold | 14.7 |
Tungsten | 33.2 |
Steel | 95.8 |
Unit of specific resistance
SI unit of specific resistance is ohm meter (Ωm)
What is electric resistivity?
Specific electrical resistance is also known as electric resistivity is a property of material defining how strongly can the material oppose the flow of electric current. SI unit of electrical resistivity is ohm-metre and is represented as ⍴.
What is airway resistance?
Airway resistance is studied in respiratory physiology and is defined as the resistance of the respiratory tract to airflow during inhaling and exhaling. Following is the formula similar to Ohm’s law:
\(R_{AW}=\frac{\Delta P}{\dot{V}}\)Where,
\(\Delta P=P_{ATM}-P_{A}\) \(R_{AW}=\frac{P_{ATM}-P_{A}}{\dot{V}}\)Where,
R_{AW}: airway resistance
ΔP: pressure difference driving airflow
P_{ATM}: atmospheric pressure
P_{A}: alveolar pressure
\(\dot{V}\) : volumetric airflowSpecific resistance of copper
The specific resistance of copper which is a good conductor is 1.72*10^{-8 }ohm meter and the specific resistivity of air which is a poor conductor is 1.5*10^{14} ohm meter.
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Related Physics articles:
The Temperature Dependence of Resistance | Resistivity and Temperature Dependence of Resistivity |
Electrical Conductors | Conductors And Insulators |