In the figure shown a current $I_1$ is established in the long straight wire $AB$.Another wire $CD$ carrying current $I_2$ is placed in the plane of the paper. The line joining the ends of this wire is perpendicular to the wire $AB$. The force on the wire $CD$ is:

A closed loop $PQRS$ carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments $PS, SR$ and $RQ$ are $F_1, F_2$ and $F_3$ respectively and are in the plane of the paper and along the directions shown, the force on the segment $QP$ is

A metallic rod of mass per unit length $0.5\; kg\; m^{-1}$ is lying horizontally on a smooth inclined plane which makes an angle of $30^o$ with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction $0.25\; T$ is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is.....$A$

$A$ and $B$ are two conductors carrying a current $i$ in the same direction. $x$ and $y$ are two electron beams moving in the same direction

Two long parallel wires are at a distance of $1$ metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is

A one metre long wire is lying at right angles to the magnetic field. A force of $1\, kg$ wt. is acting on it in a magnetic field of $0.98\, Tesla$. The current flowing in it will be....$A$