$P, Q$ and $R$ are long parallel straight wires in air,carrying currents $20 \ A, 40 \ A$ and $60 \ A$ as shown in the figure. What is the direction of the resultant force on $Q$?

$A$ wire $X$ of length $50 \; cm$ carrying a current of $2 \; A$ is placed parallel to a long wire $Y$ of length $5 \; m$. The wire $Y$ carries a current of $3 \; A$. The distance between the two wires is $5 \; cm$ and the currents flow in the same direction. The force acting on the wire $X$ due to wire $Y$ is:

$A$ single-turn current loop in the shape of a right-angled triangle with sides $5 \,cm, 12 \,cm, 13 \,cm$ carries a current of $2 \,A$. The loop is placed in a uniform magnetic field of magnitude $0.75 \,T$, whose direction is parallel to the current in the $13 \,cm$ side of the loop. The magnitude of the magnetic force on the $5 \,cm$ side is $\frac{x}{130} \,N$. The value of '$x$' is:

Two thin long parallel wires, $W_1$ and $W_2$ separated by distance '$a$',carry currents $i$ and $3i$ respectively in the same direction. The magnitude of the force per unit length exerted by wire $W_1$ on wire $W_2$ is

$A$ square loop,carrying a steady current $I$,is placed in a horizontal plane near a long straight conductor carrying a steady current $I_1$ at a distance $d$ from the conductor as shown in the figure. The loop will experience:

Obtain the expression for the force between two parallel current-carrying wires.