Question

A conductor consists of a circular loop of radius $R=10cm$ and two straight, long sections as shown in figure.The wire lies in the plane of the paper and carries a current of $i=7.00A$. Determine the magnitude and direction of the magnetic field at the centre of the loop.

Answer 1

Both straight and circular wire will produce magnetic fields inwards.
$B=\frac{{\mu }_o}{2\pi }\frac{i}{R}+\frac{{mu}_{o}i}{2R}$

$=\frac{(2\times {10}^{-7})\left(7\right)}{0.1}+\frac{(4\pi \times {10}^{-7})\left(7\right)}{2\times 0.1}$

$=5.8\times {10}^{-5}T$ into the page