Two infinitely long parallel wires having linear charge densities ${\mathrm{\lambda }}_1 \mathrm{and} {\mathrm{\lambda }}_2$ respectively, are placed at a distance of R metres. The force per unit length on either wire will be $\left(\mathrm{k}=\frac{1}{4{\mathrm{\pi \epsilon }}_0}\right)$

• A

  $\mathrm{K}\frac{2{\mathrm{\lambda }}_1{\mathrm{\lambda }}_2}{{\mathrm{R}}^2}$

• B

  $\mathrm{k}\frac{2{\mathrm{\lambda }}_1{\mathrm{\lambda }}_2}{\mathrm{R}}$

• C

  $\mathrm{k}\frac{{\mathrm{\lambda }}_1{\mathrm{\lambda }}_2}{{\mathrm{R}}^2}$

• D

  $\mathrm{k}\frac{{\mathrm{\lambda }}_1{\mathrm{\lambda }}_2}{\mathrm{R}}$