Illustration of Biot-Savart law.
Magnetic field strength $H$ is generated around a straight conductor with electric current $I$. The drawing shows the contribution to $H$ from the infinitesimal part $d \vec l$ of the conductor. The contribution is maximal directly above the contributing part $d \vec l$ and reduces with the distance and the corresponding angle.
The drawing was inspired by: McMaster University, The Biot-Savart Law, Text section 30.1, 30.2, {accessed 2020-07-25}
biot-savart_h_distribution_magnetica.png
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S. Zurek, Encyclopedia Magnetica, CC-BY-4.0
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