$A$ straight wire of mass $200 \;g$ and length $1.5 \;m$ carries a current of $2 \;A$. It is suspended in mid-air by a uniform horizontal magnetic field $B$ (Figure). What is the magnitude of the magnetic field (in $T$)?

$A$ wire loop of irregular shape carrying current is placed in an external magnetic field. If the wire is flexible,the shape of the loop changes to

Two long wires carrying currents $I_1$ and $I_2$ are arranged as shown in the figure. The wire carrying current $I_1$ is along the $x$-axis. The other wire carrying current $I_2$ is parallel to the $y$-axis,passing through the point $(0, 0, d)$. Find the magnetic force exerted on a segment of length $dl$ of the second wire at the point $O_2(0, 0, d)$ due to the wire carrying current $I_1$.

The figure shows a conducting loop $ADCA$ carrying current $i$ and placed in a region of uniform magnetic field $B_0$. The part $ADC$ forms a semicircle of radius $R$. The magnitude of the force on the semicircular part of the loop is equal to

Two long straight parallel conductors are carrying currents $i_1$ and $i_2$ in the same direction. The work done per unit length,when the distance between them is doubled,is:

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