Question

solve for the resistance of a 100m long tungsten wire which has a circular cross sectional area with a diameter of 0.1mm solutions

Answer 1

The resistance is

$$R=\rho\frac{l}{A}=\rho\frac{4l}{\pi d^2}$$

$$R=5.60\cdot 10^{-8}\frac{4(100)}{\pi (1\cdot 10^{-4})^2}=713\ \Omega$$