Field of a wire at 10 cm

Problem

Calculate the magnetic field generated by a very long straight wire, carrying a current of $10$ A, at a distance of $10$ cm from the wire.

Solution

For an infinite straight wire the field at distance $r$ is $B = \dfrac{\mu_0 i}{2\pi r}$, with $\mu_0 = 4\pi\cdot 10^{-7}$ and so $\dfrac{\mu_0}{2\pi} = 2\cdot 10^{-7}$:

$B = \frac{\mu_0 i}{2\pi r} = \frac{2\cdot10^{-7}\cdot 10}{0{,}10}$

$\ev{B = 2{,}0\cdot 10^{-5}\;\text{T}}$

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Topics: Magnetism Concepts: Magnetic field