Answer:
B = 4.5 x 10⁻⁷ T = 0.45 μT
Explanation:
From Ampere's law the magnetic field at a certain radius from straight current-carrying wire is given by the following formula:
[tex]B = \frac{\mu_oI}{2\pi r}[/tex]
where,
B = magnetic field = ?
[tex]\mu_o[/tex] = permeability of free space = 4π x 10⁻⁷ H/m
I = current = 180 A
r = radius = 80 m
Therefore,
[tex]B=\frac{(4\pi\ x\ 10^{-7}\ H/m)(180\ A)}{2\pi (80\ m)}\\\\[/tex]
B = 4.5 x 10⁻⁷ T = 0.45 μT