Moving Charges And Magnetism

Two long conductors separated by a distance ' d ' carry currents ' $\mathrm{I}_1$ ' and ' $\mathrm{I}_2$ ' in the same directions. They exert a force ' $F$ ' on each other. The distance between them is increased to ' 3 d '. If new repulsive force of magnitude ' $\frac{2}{3} \mathrm{~F}$ ' is found between these conductors, the required change in the magnitude and direction of one of the currents in the conductor is respectively [length of the conductors is constant]