Why can't I use Ampere's law to compute the magnetic field at the center (P) of a semi-circular wire?(adsbygoogle = window.adsbygoogle || []).push({});

If I calculate B at P due to d_theta, and then, using superposition, integrate from 0 to pi,

the result is B=uI/2R.

Biot-Savarte law gives the correct answer of B=uI/4R.

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# Ampere's Law and partial-circular wires.

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