Question

Define the term ‘electrical conductivity’ of a metallic wire. Write its S.I. unit.

Answer 1

Hint: The concept of electro conductivity tells the relation of electric current and metallic wire and materials and it tells about the response of materials when electric current is applied on it, use this information to answer the mentioned problem.

Complete step-by-step answer:
Conductivity can be defined as the measure of the potential of an electrolyte solution for conducting electricity.
So, the electrical conductivity of a metal wire can be defined as the degree to which a material or specified material conducts electricity. In other words, we can say that the measure of a material’s ability to allow the transport of an electric charge. Symbol of electrical conductivity is given as $\sigma $
We measure the electrical conductivity as the ratio of the material’s current density to the electrical field that causes the current to flow i.e.$\sigma = \dfrac{1}{\rho }$ where $\sigma = conductivity$ of the metallic wire and $\rho = resistivity$.From this equation we can say that electrical conductivity of the metallic wire is reciprocal to its resistivity
SI unit of electrical conductivity can be determined as:
We know conductivity = $\dfrac{{\rho l}}{A}$ where $\rho = \dfrac{1}{\sigma }$
So,$\dfrac{1}{G} = \dfrac{1}{\sigma }\dfrac{L}{A}$, $\sigma = \dfrac{{GL}}{A}$, where $\sigma $ is the electrical conductivity. So, by putting the units of G, L and A.
We get the unit of electrical conductivity $\sigma $ =$\dfrac{{\Omega {m^{ 1}}}}{{{m^2}}}$ = $\dfrac{{siemen}}{{meter}}$ here.
Thus the unit of electrical conductivity is $siemen$ ${m^{ - 1}}$

Note: If we have to measure the electrical conductivity of metals we can use ohmmeter to measure the resistance of a metal of given known length and area. The examples of electrical conductivity are Metal and plasma with high electrical conductivity and the metal which is a best electrical conductor is silver which is a metal, whereas glass, and pure water are electrical insulators which have poor electrical conductivity.