Moving Charges And Magnetism

Two long conductors separated by a distance '\(\mathrm{d}\)' carry currents \(I_1\) and \(I_2\) in the same direction. They exert a force '\(F\)' on each other. Now the current in one of them is increased to two times and its direction is reversed. The distance between them is also increased to \(3 \mathrm{~d}\). The new value of force between them is