Moving Charges And Magnetism

Two long conductors, separated by a distance '\(\mathrm{d}\)' carry currents '\(\mathrm{I}_1\)' and '\(\mathrm{I}_2\)' in the same directions. They exert a force '\(\mathrm{F}\)' on each other. Now the current in one of them is increased to two times and its direction is reversed. The distance is also increased to '\(3 \mathrm{~d}\)'. The new value of the force between them is