Answer
given,
upward current in straight wire = 28 A
attractive force per unit length = 6.7 x 10⁻⁴ N/m
distance of second wire = 6 cm = 0.06 m
a) [tex]\dfrac{F}{l} = \dfrac{\mu_0l_1l_2}{2\pi r}[/tex]
[tex]6.7 \times 10^{-4}= \dfrac{4 \pi \times 10^{-7}\times 28 \times l_2}{2\pi (0.06)}[/tex]
[tex]6.7 = 933.33 \times 10^{-3}I_p[/tex]
[tex]I_p = 7.179\ A[/tex]
B)
Force between the two wires is attractive, that automatically tells us that the currents are flowing in the same direction.
so, the current direction on the second wire is also upward.
