Question

The metal bar is AB =10mm, DA=18mm, BC =220cm and the resistivity of the metal is 0,012 micro ohms. what is its tip to tip resistance

Answer 1

Resistance of a conductor of uniform section $S$ is $R =\frac{\rho l}{S}$, where $\rho$ is electrical resistivity, $l$ is length.

The area of the cross section of the bar is $S = 10 \cdot 10^{-3} m \cdot 18 \cdot 10^{-3} m = 1.8 \cdot 10^{-4} m^2$, and the length is $l = 2.2 m$. Hence, the resistance is:

$R = \frac{0.012 \cdot 10^{-6} \Omega \cdot m \ 2.2 m\cdot }{1.8 \cdot 10^{-4} m^2} \approx 1.5 \cdot 10^{-4} \Omega$.