Field of a wire at 3 mm

Problem

A very long straight wire carries current $i = 2$ A. Calculate the magnitude of the magnetic field produced at a distance $r = 3$ mm from the wire.

Solution

For an indefinite straight wire the magnetic field at distance $r$ is (Biot-Savart law) $B = \frac{\mu_0\,i}{2\pi r} = \frac{4\pi\cdot 10^{-7}\cdot 2}{2\pi\cdot 3\cdot 10^{-3}} = \frac{2\cdot 10^{-7}\cdot 2}{3\cdot 10^{-3}}$ $\ev{B \approx 1.3\cdot 10^{-4}\;\text{T}}$

Collegamenti

Argomenti: Magnetismo Concetti: Campo magnetico