Question

Determine the force acting between two parallel current carrying conductor wires. Write theoretical definition of ampere on this basis.

Answer 1

Magnetic field at a distance $d$ due to a current carrying wire=$\frac{{\mu }_0{I}_1}{2\pi d}$

Hence the magnetic force on second wire due to this magnetic field is $B{I}_{2}l$

$F=\frac{{\mu }_0{I}_1{I}_{2}l}{2\pi d}$

The Ampere is that current which when flowing in two infinite parallel wires one metre apart produces a force between them of 2 x 10-7 N/m.