What is the net force on the rectangular coil?

$A$ long straight wire carrying a current of $25 \ A$ rests on a table as shown in the figure. Another wire $PQ$ of length $1 \ m$ and mass $2.5 \ g$ carries the same current but in the opposite direction. The wire $PQ$ is free to slide up and down. To what height $h$ will $PQ$ rise?

$A$ straight horizontal conducting rod of length $L$ and mass $M$ is suspended by two vertical wires at its ends. If $I$ is the current passing through the rod,then in order that the tension in the wires is zero,the magnetic field set up normal to the conductor is (Neglect the mass of the wire,$g$ = acceleration due to gravity).

As shown in the figure, a metallic rod of linear density $0.45\,kg\,m^{-1}$ is lying horizontally on a smooth inclined plane which makes an angle of $45^{\circ}$ with the horizontal. The minimum current flowing in the rod required to keep it stationary, when a $0.15\,T$ magnetic field is acting on it in the vertical upward direction, will be $....A$ $\{$Use $g=10\,m/s^2\}$

$A$ square loop of side $a$ hangs from an insulating hanger of a spring balance. The magnetic field of strength $B$ exists only at the lower edge. It carries a current $I$. Find the change in the reading of the spring balance if the direction of current is reversed.

$A$ rod of mass $M$ and length $l$ is suspended by two wires $P$ and $Q$. $A$ uniform magnetic field $B$ is directed into the page. When current $I$ flows through the rod,the tension in each supporting wire is: