Two thin,long,parallel wires,separated by a distance $d$,carry a current of $i$ in the same direction. They will

$A$ square coil $ABCD$ of side $L$ is carrying a current $I_1$ in the clockwise direction. $A$ straight conductor carrying current $I_2$ (upward direction) is kept parallel to side $AB$ at a distance $\frac{L}{3}$ in the plane of $ABCD$. The net force on the coil $ABCD$ is ($\mu_0 =$ magnetic permeability).

$A$ current of $10 \ A$ flows through two long parallel wires. The magnetic force per unit length on each wire is $2 \times 10^{-3} \ N/m$. If their currents are doubled and the separation between them is halved,then the magnetic force per unit length of each wire becomes $...... \times 10^{-3} \ N/m$.

$A$ massless square loop of wire of resistance $R$ supporting a mass $M$ hangs vertically with one of its sides in a uniform magnetic field $B$ directed outwards in the shaded region. $A$ d.c. voltage $V$ is applied to the loop. For what value of $V$ will the magnetic force exactly balance the weight of the supporting mass $M$? (side of loop $= L, g =$ acceleration due to gravity)

$A$ triangular shaped wire carrying $10 A$ current is placed in a uniform magnetic field of $0.5 T$,as shown in the figure. The magnetic force on segment $CD$ is $.... N$ (Given $BC = CD = BD = 5 cm$).

Three long straight wires are carrying current as shown in the diagram. The magnetic force per unit length on wire $Q$ is $..... \times 10^{-7} \ N/m$.