Question

A copper wire of length 2m and area of cross-section `1.7 xx 10^(-6)m^(2)` has a resistance of `2 xx 10^(-2)`ohms. Calculate the resistivity of copper.

Answer 1

The formula for resistivity is:
Resistivity, `rho = (R xx A)/(l)`
Here, Resistance, `R = 2 xx 10^(-2)Omega`
Area of cross-section, `A = 1.7 xx 10^(-6)m^(2)`
And, Length, `l = 2m`
So, putting these values in the above formula, we get:
`rho = (2 xx 10^(-2) xx 1.7 xx 10^(-6))/(2)`
`=1.7 xx 10^(-8) Omegam`
Thus, the resistivity of copper is `1.7 xx 10^(-8)` ohm-metre.