Question

Resistance of a metal wire of length 5m is 100ohm .If the area of cross section of the wire is 3x10-7 m2 calculate the resistivity of the metal

Answer 1

resistivity of the metal is 60 x 10'-7 ohm metre

Answer 2

Answer: The resistivity of the wire is $\rho = 0.6\times10^{-5}\Omega m$.

Explanation:

Given that,

Length of the wire l = 5 m

Resistance R = 100 ohm

Area of cross section $A=3\times10^{-7}m^2$

We know that,

The resistance of the wire is

$R = \dfrac{\rho l}{A}$......(I)

Where, $\rho$ = resistivity of the wire

L = length of the wire

A = area of cross section of the wire

Put the value in equation (I)

$100 = \dfrac{\rho \times5}{3\times10^{-7}}$

$\rho = \dfrac{100\times3\times10^{-7}}{5}$

$\rho = 60\times10^{-7}\ \Omega m$

$\rho = 0.6\times10^{-5}\Omega m$

Hence, The resistivity of the wire is $\rho = 0.6\times10^{-5}\Omega m$.