When current passing through two parallel wires force on them ...... while opposite current passes through same wire force between them ......(attraction, repulsion)

A circular loop has a radius of $5\, cm$ and it is carrying a current of $0.1\, amp$. Its magnetic moment is

Two parallel wires of length $9\, m$ each are separated by a distance $0.15\, m$. If they carry equal currents in the same direction and exerts a total force of $30 \times 10^{-7} \,N$ on each other, then the value of current must be........$amp$

Two long conductors, separated by a distance $d$ carry current $I_1$ 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 directions is reversed. The distance is also increased to $3d$. The new value of the force between them is

Two long wires carrying current ${{\rm{I}}_1}$ and ${{\rm{I}}_2}$ are arranged as shown in figure. The one carrying current ${{\rm{I}}_1}$ is along is the $\mathrm{y}$ - axis. The other carrying current ${{\rm{I}}_2}$ is along a line parallel to the yaxis given by ${\rm{x = 0}}$ and ${\rm{z = d}}$. Find the force exerted at ${{\rm{O}}_2}$ because of the wire along the ${\rm{x}}$ - axis.

Write formula for force per unit length of two parallel, conducting current carrying wire.