Question

A bird perches on a power line that carries a current of 160 A. Calculate the potential difference between the bird's feet if the resistance of the wire is $10\mu \Omega m^{-1}$ and the bird's feet are 4 cm apart?

• A. 1.6 x 10^-5 V
• B. 6.4 x 10^-5 V
• C. 3.2 x 10^-5 V
• D. 9.6 x 10^-5 V

Answer 1

The correct option is B

6.4 x 10^-5 V

The resistance of 4 cm of wire is $R=0.04\times 10\times {10}^{-6}=4\times {10}^{-7}\Omega$. The potential difference across 4 cm of wire is thus,
$V=IR=160\times 4\times {10}^{-7}=6.4\times {10}^{-5}V=64\mu V$.