$A$ metal ring of radius $r = 0.5 \, m$ with its plane normal to a uniform magnetic field $B$ of induction $0.2 \, T$ carries a current $I = 100 \, A$. The tension in newtons developed in the ring is:

The magnetic force between the wires as shown in the figure is:

$A$ straight wire is placed in a magnetic field that varies with distance $x$ from the origin as $\vec{B} = B_0 \left( 2 - \frac{x}{a} \right) \hat{k}$. The ends of the wire are at $(a, 0)$ and $(2a, 0)$ and it carries a current $I$ in the positive $x$-direction. If the force on the wire is $\vec{F} = IB_0 \left( \frac{ka}{2} \right) \hat{j}$, then the value of $k$ is:

Two thin,long,parallel wires,separated by a distance $d$,carry a current of $i$ in the same direction. They will

$A$ current of $3\, A$ is flowing in a linear conductor of length $40\, cm$. The conductor is placed in a magnetic field of strength $500\, G$ and makes an angle of $30^\circ$ with the direction of the field. The magnitude of the force experienced by the conductor is:

$A$ and $B$ are two infinitely long straight parallel conductors. $C$ is another straight conductor of length $1 \, m$ kept parallel to $A$ and $B$ as shown in the figure. Then the force experienced by $C$ is