Question

Determine the resistance of a copper wire having a length of 1km and diameter of 0.5mm

Answer 1

R=rho*l/A

R equals resistance (To find)
rho equals resistivity (material property
rho for copper equals 1.68*10^-8)
l equals length of wire (1 Km)
A equals cross sectional area of wire which can be found using the given diameter of the wire

A=pi*r^2

substitute given data in equation 1 and you will get your answer