Question

Calculate the resistance of a piece of wire of length 200cm given that it's resistivity is 5.4x10^-9 ohm meter. If the cross sectional area of the wire is 9.5x10^-5 cm^2

Answer 1

Given:

$l=2.0\:\rm m$

$\rho=5.4*10^{-9}\:\rm \Omega\cdot m$

$A=9.5*10^{-9}\:\rm m^2$

The resistance of a wire

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

$$=5.4*10^{-9}\:\rm \Omega\cdot m*\frac{2.0\:\rm m}{9.5*10^{-9}\:\rm m^2}=1.1\:\rm \Omega$$