Question

A practical matter power line carries a current of 500 A. What is the magnetic field in a house located 100m away from the power line

Answer 1

$B=\frac{\mu_0I}{2\pi r}=\frac{4\cdot\pi\cdot10^{-7}\cdot500}{2\cdot\pi\cdot100}=1\cdot10^{-6}\ (T)$ . Answer