Equal currents are flowing in three infinitely long wires along positive $x, y$ and $z$ direction. The magnetic field at a point $(0, 0, -a)$ would be ( $i =$ current in each wire)
  • A$\frac{{{\mu _0}I}}{{2\pi a}}(\hat j - \hat i)$
  • B$\frac{{{\mu _0}I}}{{2\pi a}}(\hat i - \hat j)$
  • C$\frac{{{\mu _0}I}}{{2\pi a}}(\hat i + \hat j)$
  • D$\frac{{{\mu _0}I}}{{2\pi a}}(-\hat i - \hat j)$
Medium
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