Choose the correct statement.

$A$ metal sample carrying a current along $X-$ axis with density $J_x$ is subjected to a magnetic field $B_z$ (along $z-$ axis). The electric field $E_y$ developed along $Y-$ axis is directly proportional to $J_x$ as well as $B_z$. The constant of proportionality has $SI$ unit:

$A$ conductor lies parallel to the $Z$-axis between $-1.5 \le Z < 1.5 \text{ m}$,carrying a constant current of $10.0 \text{ A}$ in the $-\hat{a}_z$ direction. For the given magnetic field $\vec{B} = 3.0 \times 10^{-4} e^{-0.2x} \hat{a}_y \text{ T}$,find the power required to move the conductor at a constant speed from $x = 0$ to $x = 2.0 \text{ m}$ in a time interval of $5 \times 10^{-3} \text{ s}$. Assume the motion is parallel to the $X$-axis. ........... $\text{W}$

$A$ very long wire $ABDMNDC$ is shown in the figure carrying current $I$. $AB$ and $BC$ parts are straight,long,and at a right angle. At $D$,the wire forms a circular turn $DMND$ of radius $R$. $AB$ and $BC$ parts are tangential to the circular turn at $N$ and $D$. The magnetic field at the centre of the circle is

The magnetic field intensity at the point $O$ of a loop with current $i$,whose shape is illustrated below is

Two parallel beams of electrons moving in the same direction produce a mutual force: