Two 10 cm long, straight wires, each carrying a current of 5A are kept parallel to each other. If each wire experienced a force of 10^–5 N, then separation between the wires is _________cm.

It should be mentioned, 10 cm wire is part of long wire.
Force experienced by unit length of wire
$=\frac{{\mathrm{\mu }}_0{\mathrm{I}}_1{\mathrm{I}}_2}{2\mathrm{\pi d}},{\mathrm{I}}_1={\mathrm{I}}_2=5\mathrm{A}$
 

Force experienced by wires of length 10 cm
$\begin{array}{l}=\frac{{\mathrm{\mu }}_0{\mathrm{I}}_1{\mathrm{I}}_2}{2\mathrm{\pi d}}\times 10\times {10}^{-2}\\ {10}^{-5}=\frac{2\times {10}^{-7}\times 5\times 5}{\mathrm{d}}\times 10\times {10}^{-2}\end{array}$
d = 50 × 10^–3 m
d = 50 × 10^–1 cm = 5 cm.