Question: A closed loop of wire ABCD consists of two semicircular segments AB and CD of radii R1 = 2.00 cm and R2 = 4.00 cm, and two straight segments BC and DA. The loop is carrying current I = 15.0 A.
Find the magnitude and direction of magnetic field B→ at the center of semicircles 0. (Hint: carefully use Biot-Savart law for each segment of the current loop)
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