A current carrying loop ABCDA is carrying a current I. O is the centre of the semi circle ADC, $\overline{)\mathrm{ABC}}={90}^0$ and AB = BC = l. Then magnetic induction at o is

 

• A

  $\left(\frac{1}{\mathrm{\pi }}+\frac{1}{2}\right)\frac{{\mathrm{\mu }}_{\mathrm{o}}\mathrm{{\rm I}}}{\sqrt{2}\mathcal{l}}$

• B

  $\left(\frac{8}{\mathrm{\pi }}+\frac{1}{2\sqrt{2}}\right)\frac{{\mathrm{\mu }}_{\mathrm{o}}\mathrm{{\rm I}}}{\mathcal{l}}$

• C

  $\left(\frac{4}{\mathrm{\pi }}+\frac{1}{\sqrt{2}}\right)\frac{{\mathrm{\mu }}_{\mathrm{o}}\mathrm{{\rm I}}}{\mathcal{l}}$

• D

  $\left(\frac{\sqrt{2}}{\mathrm{\pi }}+\frac{1}{2\sqrt{2}}\right)\frac{{\mathrm{\mu }}_{\mathrm{o}}\mathrm{{\rm I}}}{\mathcal{l}}$