Answer:
0.4 m
Explanation:
The magnetic field strength is given by the formula ...
B = (μ₀I)/(2πr)
where I is the current in the wire in amperes, and r is the distance from the wire in meters. The value of μ₀ is 4π×10^-7. We want to find r for B = 5×10^-5. This gives ...
5×10^-5 = (4π×10^-7)(100)/(2πr)
r = 2×10^-5/(5×10^-5) = 0.4
At a distance of 0.4 meters from the wire, the magnetic field is equal to that of Earth.
