Answer:
[tex]1.0 \cdot 10^{-5}V[/tex]
Explanation:
First of all, we need to calculate the resistance of the piece of copper wire between the bird's feet, which is given by
[tex]R=\rho \frac{L}{A}[/tex]
where:
[tex]\rho = 1.68 \cdot 10^{-8} \Omega m[/tex] is the resistivity of copper
[tex]L = 2.1 cm = 0.021 m[/tex] is the length of the piece of wire between the bird's feet
[tex]A=\pi r^2[/tex] is the cross-sectional area of the wire, with r being the radius. Since the radius is half the diameter:
[tex]r=\frac{3.5 cm}{2}=1.75 cm=0.0175 m[/tex]
the area is
[tex]A=\pi (0.0175 m)^2=9.34 \cdot 10^{-4} m^2[/tex]
And the resistance is
[tex]R=(1.68\cdot 10^{-8} \Omega m \frac{0.0175 m}{9.34 \cdot 10^{-4} m^2}=3.15\cdot 10^{-7}\Omega[/tex]
And given the current in the wire, I=32 A, we can calculate the potential difference across the bird's body by using Ohm's law:
[tex]V=IR=(32 A)(3.15\cdot 10^{-7} \Omega)=1.0 \cdot 10^{-5}V[/tex]
