Currents of $10 \ A$ and $2 \ A$ are passed through two parallel wires $A$ and $B$ respectively in opposite directions. If the wire $A$ is infinitely long and the length of the wire $B$ is $2 \ m$,the force acting on the conductor $B$,which is situated at a distance of $10 \ cm$ from $A$,will be . . . . . . .

$A$ magnetic field is in the $+Y$ direction. $A$ current $i$ flows through the wire $PQRSTU$. Each side has a length $L$. What is the net force on the wire?

Two long straight wires $A$ and $B$ carrying equal current $I$ were kept parallel to each other at distance $d$ apart. The magnitude of the magnetic force experienced by length $L$ of wire $A$ is $F$. If the distance between the wires is halved and the currents are doubled,the force $F_2$ on length $L$ of wire $A$ will be:

$A$ thin uniform rod with negligible mass and length $l$ is attached to the floor by a frictionless hinge at point $P$. $A$ horizontal spring with force constant $k$ connects the other end to a wall. The rod is in a uniform magnetic field $B$ directed into the plane of the paper. What is the extension in the spring in equilibrium when a current $i$ is passed through the rod in the direction shown? Assume the spring is initially at its natural length.

$A$ square loop $ABCD$ of side length $L$,carrying a current $i$,is placed near and coplanar with a long straight conductor $XY$ carrying a current $I$. The distance between the conductor and the side $AB$ is $L/2$. The net force on the loop will be:

$A$ rigid square loop of side $a$ carrying current $I_2$ is lying on a horizontal surface near a long wire carrying current $I_1$ in the same plane as shown in the figure. The net force on the loop due to the wire will be: