$A$ wire carrying a current $I$ is placed inside a uniform magnetic field $\vec{B} = -B_0 \hat{k}$. The shape of the wire is parabolic and has the equation $y = 2x - x^2$. The force on the wire will be:

$AB$ and $CD$ are smooth parallel rails,separated by a distance $l$,and inclined to the horizontal at an angle $\theta$. $A$ uniform magnetic field of magnitude $B$,directed vertically upwards,exists in the region. $EF$ is a conductor of mass $m$,carrying a current $i$. For $EF$ to be in equilibrium,

$A$ square loop of edge length $2 \ m$ carrying current of $2 \ A$ is placed with its edges parallel to the $x-y$ axis. $A$ magnetic field is passing through the $x-y$ plane and expressed as $\vec{B}=B_0(1+4x) \hat{k}$,where $B_0=5 \ T$. The net magnetic force experienced by the loop is . . . . . . $N$.

Assertion $(A):$ $A$ wire is bent into an irregular shape with the points $P$ and $Q$ fixed. If a current $I$ is passed through the wire,then the area enclosed by the irregular portion of the wire increases.
Reason $(R):$ Wires carrying currents in opposite directions repel each other.

$A$ semi-circular loop of radius $30 \,cm$ wire carries current $6 \,A$. $A$ uniform magnetic field $0.5 \,T$ is present perpendicular to the plane of the loop. What is the magnitude of force exerted on the wire (in $\,N$)?

Three straight parallel current-carrying conductors are shown in the figure. The force experienced by the middle conductor of length $25\, cm$ is