Question

A wire of resistance 4.5 ohm and length 150 cm has area of cross section is 0.04 cm2 calculate resistivity of wire

Answer 1

Here is the solution of question.

Answer 2

Explanation :

Resistance of the wire, $R=4.5\ \Omega$

Length of wire, $l=150\ cm=1.5\ m$

Area of cross section, $A=0.04\ cm^2=4\times 10^{-6}\ m^2$

The relation between resistivity and the resistance of the wire is :

$R=\rho\dfrac{l}{A}$

or

$\rho=R\dfrac{A}{l}$

$\rho=4.5\ \Omega\times \dfrac{4\times 10^{-6}\ m^2}{1.5\ m}$

$\rho=0.000012\ \Omega-m$

or

$\rho=1.2\times 10^{-5}\ \Omega-m$

Hence, this is the required solution.