A vertical straight wire carring and an upward 12A current exerts and attractive force per unit length of?

Question

0.00088 N/m on a second parallel wire 7 cm away. what current ( magnitude and direction ) flows in the second ??

Answer 1

F/L = µ*I1*I2/(2πD) ==> I2 = (2FπD/L)/(µ*I1) = 25.6666667 A

Since the force is attractive, both currents are in the same direction.

See the ref.

µ is free-space permeability = 4π*1E-7 = 1.25663706E-06 N/A^2