Question

There are $100$ turns in a circular coil of a wire, the radius of each is $8.0cm$ and in this $0.40A$ current is flowing. What will be the magnitude of the magnetic field at the centre of the coil?

Answer 1

Number of turns in coil $N=100$
Radius $R=8.0cm=8\times {10}^{-2}m$
Flowing current $I=0.40A$
Magnetic field at the centre of coil
$B=\frac{{\mu }_{0}NI}{2r}$
$B=\frac{4\pi \times {10}^{-7}\times 100\times 0.40}{2\times 8\times {10}^{-2}}$
$B=3.1\times {10}^{-4}T$