Question

If a wire made up of unknown material is 25.0 m long with a diameter of 0.100 mm and has a resistance of 77.7Ω at 20.0°C, What is its resistance at 186 °C?

Round your answer to 2 decimal places

Answer 1

$$R=\rho\frac{l}{0.25\pi d^2}\\77.7=\frac{25}{0.25\pi (1\cdot10^{-4})^2}\rho\\\rho=2.44\cdot10^{-8}\Omega m$$

It is Gold!

$$R'=77.7(1+(0.0034)(186-20))=121.6\Omega$$