Three long current carrying wires $P, Q$ and $R$ placed perpendicular to plane of the paper. Magnetic force per unit length on wire $'R'$ is

If a wire of length $1\, meter$ placed in uniform magnetic field $1.5\, Tesla$ at angle ${30^o}$ with magnetic field. The current in a wire $10\, amp$. Then force on a wire will be.......$N$

Two long parallel copper wires carry currents of $5\,A$ each in opposite directions. If the wires are separated by a distance of $0.5\,m$, then the force between the two wires is

Write formula for force per unit length of two parallel, conducting current carrying wire.

Derive an expression for the force per unit length between two infinitely long straight parallel current carrying wires. Hence, define one ampere $( \mathrm{A} )$.

What is the magnitude of magnetic force per unit length on a wire carrying a current of $8\,A$ and making an angle of $30^o$ with the direction of a uniform magnetic field of $0.15\, T$ ?.....$Nm^{-1}$