Question
Magnetic field at the centre $O$ due to the given structure is

Answer

(c)

$B=B_{\text {due to circular arc }}+B_{\text {due to straight wires }}$

$=\frac{\mu_0 i}{2 R}\left(\frac{3 \pi}{2 \cdot(2 \pi)}\right)+\frac{\mu_0 i}{4 \pi R}$

$\Rightarrow B=\frac{\mu_0 i}{4 R}\left(\frac{3}{2}+\frac{1}{\pi}\right) \otimes$

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