Question

A closely wound, circular coil with radius 2.40 cm has 800 turns. What must be the approximate current (A) in the coil if the magnetic field at the centre of the coil is 0.0580 T?

Answer 1

Magnetic field at the center of a circular coil is $B=\frac{{\mu }_{0}NI}{2R}$

$⟹I=\frac{2BR}{{\mu }_{0}N}$
$=\frac{2\times 0.058\times 0.024}{{\mu }_0\times 800}$

$\approx 3$