Question

me ajudem POR FAVOR !!!!

Answer 1

$B = \frac{\mu_0 I}{2 \pi R}\\B = \frac{4 \cdot \pi \cdot 10^{-7} \cdot 4 \cdot 10^{-3}}{2 \cdot \pi \cdot 8 \cdot 10^{-2}} \\B = 1 \cdot 10^{-8} \ \text{T}$