An elastic circular wire of length $l$ carries a current $I$. It is placed in a uniform magnetic field $\vec{B}$ (out of the paper) such that its plane is perpendicular to the direction of $\vec{B}$. The wire will experience:

Two parallel wires of length $9 \, m$ each are separated by a distance $0.15 \, m$. If they carry equal currents in the same direction and exert a total force of $30 \times 10^{-7} \, N$ on each other,then the value of current must be ........ $A$. (in $.5$)

An infinitely long current-carrying wire and a small current-carrying loop are in the plane of the paper as shown. The radius of the loop is $a$ and the distance of its centre from the wire is $d$ $(d >> a)$. If the loop applies a force $F$ on the wire,then:

$A, B$ and $C$ are parallel conductors of equal length carrying currents $I, I$ and $2I$ respectively. The distance between $A$ and $B$ is $x$. The distance between $B$ and $C$ is also $x$. If $F_1$ is the force exerted by $B$ on $A$ and $F_2$ is the force exerted by $C$ on $B$,choose the correct answer.

Give the uses of electromagnets.

The figure shows three long straight wires $P, Q$ and $R$ carrying currents normal to the plane of the paper. All three currents have the same magnitude. Which arrow best shows the direction of the resultant force on the wire $P$?