Answer:
d = 15 mm
Explanation:
Force of repulsion between two current carrying wire is given by
[tex]F = \frac{\mu_0 i_1 i_2 L}{2\pi d}[/tex]
now this force of repulsion is counterbalanced by the weight of the wire
so we have
[tex]mg = \frac{\mu_0 i_1 i_2 L}{2\pi d}[/tex]
now we have
[tex]d = \frac{\mu_0 i_1 i_2 L}{2\pi mg}[/tex]
so here we can say that
[tex]d = \frac{\mu_0 i_1 i_2}{2\pi (m/L)g}[/tex]
now plug in all values in it
[tex]d = \frac{4\pi \times 10^{-7} (72.8)(72.7)}{2\pi (0.071)}[/tex]
[tex]d = 0.015 m[/tex]
d = 15 mm