Question

Question 5
Use the data in Table to answer the following –

(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?

Table: Electrical resistivity of some substances at ${20}^{\circ }C$
$\begin{array}{ccc}& Material& Resistivity\left(\Omega m\right)\\ Conductors& Silver& 1.60\times {10}^{-8}\\ & Copper& 1.62\times {10}^{-8}\\ & Aluminium& 2.63\times {10}^{-8}\\ & Tungsten& 5.20\times {10}^{-8}\\ & Nickel& 6.84\times {10}^{-8}\\ & Iron& 10.0\times {10}^{-8}\\ & Chromium& 12.9\times {10}^{-8}\\ & Mercury& 94.0\times {10}^{-8}\\ & Manganese& 1.84\times {10}^{-6}\\ Alloys& Constantan\left(alloyofCuNi\right)& 49\times {10}^{-6}\\ & Manganin(alloyofCu,MnandNi)& 44\times {10}^{-6}\\ & Nichrome(alloyofNi,Cr,MnandFe)& 100\times {10}^{-6}\\ Insulators& Glass& {10}^{10}-{10}^{14}\\ & Hardrubber& {10}^{13}-{10}^{16}\\ & Ebonite& {10}^{15}-{10}^{17}\\ & Diamond& {10}^{12}-{10}^{13}\\ & Paper\left(dry\right)& {10}^{12}\end{array}$

Answer 1

(a) Resistivity of iron = $10.0\times {10}^{-8}\Omega m$
Resistivity of mercury = $94.0\times {10}^{-8}\Omega m$
The resistivity of mercury is more than that of iron. This implies that iron is a better conductor than mercury.
(b) It can be observed from the table that the resistivity of silver is the lowest among the listed materials. Hence, it is the best conductor.