In the given figure,what is the ratio of the magnetic force on wire $ab$ to that on wire $bc$? (Given $ab = l$ and $\angle abc = 45^o$)

An infinitely long,straight conductor $AB$ is fixed and a current $i_1$ is passed through it. Another movable straight wire $CD$ of finite length carrying current $i_2$ is held perpendicular to it and released. Neglect the weight of the wire.

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

Two long conductors separated by a distance $d$ carry currents $I_1$ 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 $2$ times and its direction is reversed. The distance between them is also increased to $3d$. The new value of force between them is:

$A$ rectangular loop of wire,supporting a mass $m$,hangs with one end in a uniform magnetic field $\vec B$ pointing into the plane of the paper. $A$ clockwise current $i$ is set up such that $i > mg/Ba$,where $a$ is the width of the loop. Then:

If two streams of protons move parallel to each other in the same direction,then they