Question

An infinitely long conductor has a circular loop tangent to it. A current of 5 A flows through the conductor. Find the radius of the loop if the intensity of the magnetic field at its centre is 41 A/m.

Answer 1

We know that

$B=\frac{\mu_0 ni}{2r}$

Now $B=\mu_0H$

Both equation equal

$\mu_0H=\frac{\mu_0 ni}{2r}$

$H=\frac{ni}{2r}$

Put n=1

i=5A

H=41A/m

Put value

$41=\frac{1\times5}{2\times r}$

$r=\frac{5}{82}=0.060m$