Question

The force between two parallel current-carrying wires is independent of

• A. their distance of separation
• B. the length of the wires
• C. the magnitude of currents
• D. the radii of the wires

Answer 1

Answer: (D)

The force between two current-carrying conductors can be given by
$\frac{F}{L}=\frac{{\mu }_0{I}_1{I}_2}{2\pi d}$
where,
$F$ = force on each conductor
$L$ = Length of the conductor
$I_1,I_2$ = current in the conductors
$d$ = distance between the conductors
Hence, we can say the force between two parallel current-carrying wires is independent of the radii of the wires.