A long wire A carries a current of 10 A. Another long wire B, which is parallel to A and separated by 0.1 m from A, carries a current of 5 A, in the opposite direction to that in A. What is the magnitude and nature of the force experienced per unit length of B?

$\left({\mathrm{\mu }}_0=4\mathrm{\pi }\times {10}^{-7}\mathrm{Wb}/\mathrm{A}-\mathrm{m}\right)$

• A

  $\mathrm{Repulsive}\mathrm{force}\mathrm{of}{10}^{-4}\mathrm{N}/\mathrm{m}$

• B

  $\mathrm{Attractive}\mathrm{force}\mathrm{of}{10}^{-4}\mathrm{N}/\mathrm{m}$

• C

  $\mathrm{Repulsive}\mathrm{force}\mathrm{of}2\mathrm{\pi }\times {10}^{-5}\mathrm{N}/\mathrm{m}$

• D

  $\mathrm{Attractive}\mathrm{force}\mathrm{of}2\mathrm{\pi }\times {10}^{-5}\mathrm{N}/\mathrm{m}$