$A$ straight wire of length $50 \text{ cm}$ carrying a current of $2.5 \text{ A}$ is suspended in mid-air by a uniform magnetic field of $0.5 \text{ T}$. Calculate the mass of the wire. (Take $g = 10 \text{ m s}^{-2}$) (in $\text{ g}$)

$A$ metallic rod of mass per unit length $0.5\; kg\; m^{-1}$ is lying horizontally on a smooth inclined plane which makes an angle of $30^{\circ}$ with the horizontal. The rod is prevented from sliding down by passing a current through it,while a magnetic field of induction $0.25\; T$ acts on it in the vertical direction. The current flowing in the rod to keep it stationary is: (in $; A$)

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 . . . . . . .

Write the magnetic force equation on a current-carrying element $I\vec{dl}$ inside a magnetic field $\vec{B}$. Write the law used to determine the direction of the magnetic force.

Three long,straight parallel wires carrying current are arranged as shown in the figure. The force experienced by a $25\, cm$ length of wire $C$ is

Wires $1$ and $2$ carrying currents $i_1$ and $i_2$ respectively are inclined at an angle $\theta$ to each other. What is the force on a small element $dl$ of wire $2$ at a distance of $r$ from wire $1$ (as shown in figure) due to the magnetic field of wire $1$?